feat(router): add support for azure key vault as secret manager

[Rafee-Mohamed]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Implement Azure key vault support for secret management and encryption management in external_services similar to the available AWS KMS, HashiCorp Vault, plaintext. This can be used to securely storing sensitive configuration settings.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

Fixes #6181

How did you test it?

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
Cargo.lock	Unsupported file format
crates/external_services/Cargo.toml	Unsupported file format
crates/external_services/src/azure_key_vault.rs	0% smaller
crates/external_services/src/azure_key_vault/core.rs	0% smaller
crates/external_services/src/azure_key_vault/implementers.rs	0% smaller
crates/external_services/src/lib.rs	0% smaller

[Rafee-Mohamed]

Hi everyone,

This is my first pull request to Hyperswitch. The issue is not yet fully resolved and require further guidance on resolving that. I have few doubts which I will raise in the issue comments. I would appreciate any feedback or review you may have.

Created Files:

• crates/external_services/src/azure_key_vault.rs
• crates/external_services/src/azure_key_vault/core.rs
• crates/external_services/src/azure_key_vault/implementers.rs

Thank you!