Introduce new authenticator properties: DefinedBy

[Thisara-Welmilla]

Feature

• Support for external custom authention extension #20809

With this following properties will be introduce to the authenticator configs and Application Authenticators.

• DefinedBy - to indicate whether the authenticator is system-defined or user-defined.

1. SYSTEM: Sytem defined authenticators, all the existing authenticators are this type.
2. USER: User defined authenticators, all the custom authenticators of authentication extension come under this type.

[Thisara-Welmilla]

Related PRs:

• Add definedBy property for authenticator databases. carbon-identity-framework#5991
• Add definedBy property for authenticators. carbon-identity-framework#5990
• Add definedBy property for authenticator identity-api-server#679
• Improve framework to resolve the definedBy authenticator property carbon-identity-framework#6029

Fix unit tests:

• Improve unit tests for introducing new authenticator property carbon-identity-framework#6017

Integration tests:

• Improve integration tests on the definedBy authentication property #21315
• Update OpenIDConnectAuthenticator name in integration tests. #21381