Provide API for the new custom authentication management

[Thisara-Welmilla]

Feature

• Support for external custom authention extension #20809

This update provides API support for creating new custom authenticators for one of the following types, enabling user authentication with an external authentication service:

1. External User Account Authentication: This authenticator can authenticate federated users and provision them.
2. Internal User Account Authentication: This authenticator collects identifiers and authenticates user accounts managed within the organization.
3. 2FA Authentication: This authenticator verifies users in the second or subsequent steps of the login process.

Tasks:

• Update yaml files with new API capabilities.
• Improve authentication configuration API layer to support the custom authentication management.
• Improve authentication configuration service layer to support the custom authentication management.
• Unit tests for new improvements.

[Thisara-Welmilla]

PR:

• Add new authenticator configs for user defined authentication extensions. carbon-identity-framework#6108

Update /identity-provider/ API to manage user defined federated authenticators

• API layer: Update the /identity-providers/ API to manage user-defined federated authenticators. identity-api-server#735
• Service layer: Add support for managing custom federated authenticators. carbon-identity-framework#6105

Update /configs/authenticators/{authenticator_id} API to return user defined local authenticators.

• Service layer: Update /configs/authenticators/{authenticator_id} API to return user defined local authenticators. identity-api-server#734

New /authenticators/custom API to manage user defined local authenticators.

• Service layer: Add service layer support to manage the user defined local authenticators carbon-identity-framework#6071