Issue:
feat(verify): add new types for validate API

## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates

## Description
This part of series of PR's which are aimed at adding ValidateAPI in the core. This PR specifically deals with introducing new types for the Flows and Operations which are to be added going further.
<!-- Describe your changes in detail -->


### Additional Changes

- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

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Provide links to the files with corresponding changes.

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1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
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## Motivation and Context
Here, the intension is adding a new Validation feature in PaymentsCore, for that reason following are the steps that the change is broken down to. 
1. Create new types for the change
2. Introduce the Flow and Connector Integration
3. Add Stripe POC
4. Move the mandate related behaviour to domain
5. Introduce the new operation and all the related components in the payments core
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## How did you test it?
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## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt`
- [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


Resolution:
<think>
PR Context:
- Title: feat(verify_flow): add a new flow `Verify` [blocked on #45]
- Merged: 2022-12-06T06:20:10Z
- Files changed: 13 files
- Commits: 1 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates

## Description
This PR primarily focuses on adding a new flow `Verify` in the core implementation and all the implementation that come along with it
<!-- Describe your changes in detail -->


### Additional Changes

- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variabl
</think>

To implement this, you'll need to modify:


(No detailed commit information available)