Issue: [FEATURE] add payments get-intent API for v2

# Feature Description
Add payments `get-intent` API for v2

Resolution: <think>
PR Context:
- Title: feat(router): Add payments get-intent API for v2
- Merged: 2024-10-30T16:28:52Z
- Files changed: 18 files
- Commits: 8 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
Added `get-intent` API for payments

### Additional Changes

- [x] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** feat(router): Add payments get-intent API for v2 (#6396)
Co-authored-by: hyperswitch-bot[bot] <14852
Files to modify:


**crates/api_models/src/events/payment.rs**
  Remove:
    - impl: impl ApiEventMetric for PaymentsCreateIntentResponse
  Add:
    - function: private::get_api_event_type
    - impl: impl ApiEventMetric for PaymentsGetIntentRequest
    - impl: impl ApiEventMetric for PaymentsIntentResponse

**crates/api_models/src/payments.rs**
  Remove:
    - struct: pub::PaymentsCreateIntentResponse
  Add:
    - struct: pub::PaymentsGetIntentRequest
    - struct: pub::PaymentsIntentResponse

**crates/hyperswitch_domain_models/src/router_flow_types/payments.rs**
  Remove:
    - struct: pub::CreateIntent
  Add:
    - struct: pub::PaymentCreateIntent
    - struct: pub::PaymentGetIntent

**crates/openapi/src/openapi_v2.rs**
  Modify existing code

**crates/openapi/src/routes/payments.rs**
  Add:
    - function: pub::payments_get_intent

**crates/router/src/core/payments.rs**
  Modify existing code

**crates/router/src/core/payments/operations.rs**
  Remove:
    - mod: pub::payment_confirm_intent
  Add:
    - mod: pub::payment_confirm_intent
    - mod: pub::payment_get_intent

**crates/router/src/core/payments/operations/payment_get_intent.rs**
  Add:
    - function: private::to_validate_request
    - function: private::to_get_tracker
    - function: private::to_domain
    - function: private::to_update_tracker
    - function: private::to_validate_request
    - function: private::to_get_tracker
    - function: private::to_domain
    - function: private::to_update_tracker
    - function: private::get_trackers
    - function: private::update_trackers
    - function: private::validate_request
    - function: private::get_customer_details
    - function: private::make_pm_data
    - function: private::get_connector
    - function: private::guard_payment_against_blocklist
    - struct: pub::PaymentGetIntent
    - impl: impl Operation<F, PaymentsGetIntentRequest> for &PaymentGetIntent
    - impl: impl Operation<F, PaymentsGetIntentRequest> for PaymentGetIntent
    - impl: impl GetTracker<F, payments::PaymentIntentData<F>, PaymentsGetIntentRequest> for PaymentGetIntent
    - impl: impl UpdateTracker<F, payments::PaymentIntentData<F>, PaymentsGetIntentRequest> for PaymentGetIntent
    - impl: impl ValidateRequest<F, PaymentsGetIntentRequest, payments::PaymentIntentData<F>> for PaymentGetIntent
    - impl: impl Domain<F, PaymentsGetIntentRequest, payments::PaymentIntentData<F>> for PaymentGetIntent

**crates/router/src/core/payments/transformers.rs**
  Remove:
    - impl: impl ToResponse<F, D, Op> for api::PaymentsCreateIntentResponse
  Add:
    - impl: impl ToResponse<F, D, Op> for api::PaymentsIntentResponse

**crates/router/src/routes/app.rs**
  Modify existing code

**crates/router/src/routes/lock_utils.rs**
  Modify existing code

**crates/router/src/routes/payments.rs**
  Add:
    - function: pub::payments_get_intent

**crates/router/src/services/api.rs**
  Remove:
    - impl: impl Authenticate for api_models::payments::PaymentsCreateIntentRequest

**crates/router/src/types/api/payments.rs**
  Modify existing code

**crates/router_env/src/logger/types.rs**
  Modify existing code