Issue:
Bug: Support Wechatpay Scan and Pay





Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [x] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
Implemented Wechatpay digital wallet, payment method for Stripe.


### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables


## Motivation and Context
In Stripe connector Wechatpay was not implemented, but it is important payment method which is needed in market so I implemented it.

Closes #242.

## How did you test it?
I tested it using Postman
<img width="1728" alt="Screenshot 2023-05-04 at 2 37 58 PM" src="https://user-images.githubusercontent.com/131388445/236166786-0f534d8f-1073-4b9d-b14f-e3537ef3fe8e.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 01 PM" src="https://user-images.githubusercontent.com/131388445/236166855-9e5badf6-ac26-4430-a04a-9bd14e8fa718.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 06 PM" src="https://user-images.githubusercontent.com/131388445/236166870-8f1297fd-ff2c-4f14-b8b9-b77c1be5636d.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 10 PM" src="https://user-images.githubusercontent.com/131388445/236166911-dc2973b9-ad7f-4f53-916e-db21da9e6f71.png">


## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed submitted code
- [ ] I added unit tests for my changes where possible
- [ ] I added a [CHANGELOG](/CHANGELOG.md) entry if applicable


Testing:
I tested it using Postman
<img width="1728" alt="Screenshot 2023-05-04 at 2 37 58 PM" src="https://user-images.githubusercontent.com/131388445/236166786-0f534d8f-1073-4b9d-b14f-e3537ef3fe8e.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 01 PM" src="https://user-images.githubusercontent.com/131388445/236166855-9e5badf6-ac26-4430-a04a-9bd14e8fa718.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 06 PM" src="https://user-images.githubusercontent.com/131388445/236166870-8f1297fd-ff2c-4f14-b8b9-b77c1be5636d.png">
<img width="1728" alt="Screenshot 2023-05-04 at 2 38 10 PM" src="https://user-images.githubusercontent.com/131388445/236166911-dc2973b9-ad7f-4f53-916e-db21da9e6f71.png">

Patch:
diff --git a/crates/router/src/connector/stripe/transformers.rs b/crates/router/src/connector/stripe/transformers.rs
index 4538ae2d140..5124b0064d9 100644
--- a/crates/router/src/connector/stripe/transformers.rs
+++ b/crates/router/src/connector/stripe/transformers.rs
@@ -298,6 +298,7 @@ pub enum StripeWallet {
     ApplepayToken(StripeApplePay),
     GooglepayToken(GooglePayToken),
     ApplepayPayment(ApplepayPayment),
+    WechatpayPayment(WechatpayPayment),
     AlipayPayment(AlipayPayment),
 }
 
@@ -333,6 +334,22 @@ pub struct AlipayPayment {
     pub payment_method_data_type: StripePaymentMethodType,
 }
 
+#[derive(Debug, Eq, PartialEq, Serialize)]
+pub struct WechatpayPayment {
+    #[serde(rename = "payment_method_types[]")]
+    pub payment_method_types: StripePaymentMethodType,
+    #[serde(rename = "payment_method_data[type]")]
+    pub payment_method_data_type: StripePaymentMethodType,
+    #[serde(rename = "payment_method_options[wechat_pay][client]")]
+    pub client: WechatClient,
+}
+
+#[derive(Debug, Eq, PartialEq, Serialize, Clone, Copy)]
+#[serde(rename_all = "snake_case")]
+pub enum WechatClient {
+    Web,
+}
+
 #[derive(Debug, Eq, PartialEq, Serialize)]
 pub struct GooglepayPayment {
     #[serde(rename = "payment_method_data[card][token]")]
@@ -361,6 +378,8 @@ pub enum StripePaymentMethodType {
     Becs,
     #[serde(rename = "bacs_debit")]
     Bacs,
+    #[serde(rename = "wechat_pay")]
+    Wechatpay,
     Alipay,
 }
 
@@ -819,6 +838,15 @@ fn create_stripe_payment_method(
                 StripeBillingAddress::default(),
             )),
 
+            payments::WalletData::WeChatPayRedirect(_) => Ok((
+                StripePaymentMethodData::Wallet(StripeWallet::WechatpayPayment(WechatpayPayment {
+                    client: WechatClient::Web,
+                    payment_method_types: StripePaymentMethodType::Wechatpay,
+                    payment_method_data_type: StripePaymentMethodType::Wechatpay,
+                })),
+                StripePaymentMethodType::Wechatpay,
+                StripeBillingAddress::default(),
+            )),
             payments::WalletData::AliPay(_) => Ok((
                 StripePaymentMethodData::Wallet(StripeWallet::AlipayPayment(AlipayPayment {
                     payment_method_types: StripePaymentMethodType::Alipay,
@@ -832,7 +860,6 @@ fn create_stripe_payment_method(
                 StripePaymentMethodType::Card,
                 StripeBillingAddress::default(),
             )),
-
             _ => Err(errors::ConnectorError::NotImplemented(
                 "This wallet is not implemented for stripe".to_string(),
             )
@@ -1251,8 +1278,9 @@ impl ForeignFrom<(Option<StripePaymentMethodOptions>, String)> for types::Mandat
                 | StripePaymentMethodOptions::Ach {}
                 | StripePaymentMethodOptions::Bacs {}
                 | StripePaymentMethodOptions::Becs {}
-                | StripePaymentMethodOptions::Sepa {}
-                | StripePaymentMethodOptions::Alipay {} => None,
+                | StripePaymentMethodOptions::WechatPay {}
+                | StripePaymentMethodOptions::Alipay {}
+                | StripePaymentMethodOptions::Sepa {} => None,
             }),
             payment_method_id: Some(payment_method_id),
         }
@@ -1412,6 +1440,7 @@ pub enum StripeNextActionResponse {
     RedirectToUrl(StripeRedirectToUrlResponse),
     AlipayHandleRedirect(StripeRedirectToUrlResponse),
     VerifyWithMicrodeposits(StripeVerifyWithMicroDepositsResponse),
+    WechatPayDisplayQrCode(StripeRedirectToQr),
 }
 
 impl StripeNextActionResponse {
@@ -1420,6 +1449,7 @@ impl StripeNextActionResponse {
             Self::RedirectToUrl(redirect_to_url) | Self::AlipayHandleRedirect(redirect_to_url) => {
                 redirect_to_url.url.to_owned()
             }
+            Self::WechatPayDisplayQrCode(redirect_to_url) => redirect_to_url.data.to_owned(),
             Self::VerifyWithMicrodeposits(verify_with_microdeposits) => {
                 verify_with_microdeposits.hosted_verification_url.to_owned()
             }
@@ -1453,6 +1483,11 @@ pub struct StripeRedirectToUrlResponse {
     url: Url,
 }
 
+#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
+pub struct StripeRedirectToQr {
+    data: Url,
+}
+
 #[derive(Clone, Debug, Eq, PartialEq, Deserialize)]
 pub struct StripeVerifyWithMicroDepositsResponse {
     hosted_verification_url: Url,
@@ -1612,8 +1647,8 @@ pub struct StripeBillingAddress {
 
 #[derive(Debug, Clone, serde::Deserialize, Eq, PartialEq)]
 pub struct StripeRedirectResponse {
-    pub payment_intent: String,
-    pub payment_intent_client_secret: String,
+    pub payment_intent: Option<String>,
+    pub payment_intent_client_secret: Option<String>,
     pub source_redirect_slug: Option<String>,
     pub redirect_status: Option<StripePaymentStatus>,
     pub source_type: Option<Secret<String>>,
@@ -1657,6 +1692,7 @@ pub enum StripePaymentMethodOptions {
     Becs {},
     #[serde(rename = "bacs_debit")]
     Bacs {},
+    WechatPay {},
     Alipay {},
 }
 
@@ -1945,6 +1981,14 @@ impl
                     Ok(Self::Wallet(wallet_info))
                 }
 
+                payments::WalletData::WeChatPayRedirect(_) => {
+                    let wallet_info = StripeWallet::WechatpayPayment(WechatpayPayment {
+                        client: WechatClient::Web,
+                        payment_method_types: StripePaymentMethodType::Wechatpay,
+                        payment_method_data_type: StripePaymentMethodType::Wechatpay,
+                    });
+                    Ok(Self::Wallet(wallet_info))
+                }
                 payments::WalletData::AliPay(_) => {
                     let wallet_info = StripeWallet::AlipayPayment(AlipayPayment {
                         payment_method_types: StripePaymentMethodType::Alipay,