[FEATURE] Payments V2 supporting confirm intent API via External vault

[su-shivanshmathur]

Feature Description

Make payment-confirm API support external vault and replace the card data with tokens whose value will be with the external vault.

Possible Implementation

Use proxy service provided by these external vault to support payment completion in Payments V2

Have you spent some time checking if this feature request has been raised before?

• [x] I checked and didn't find a similar issue

Have you read the Contributing Guidelines?

• [x] I have read the Contributing Guidelines

Are you willing to submit a PR?

None