Carbon registry usage removal from SAML

[Osara-B]

Is your feature request related to a problem? Please describe.

The SAML configurations of the Identity Server currently uses the Registry as its storage repository, which is a roadblock to the plan to remove the Registry from the Identity Server.

This is part of the larger effort to remove the Registry from the Identity Server, which will help lower operational and product maintenance costs.

Describe the solution you would prefer
Need to find an alternative solution for managing SAML configuration data that doesn’t depend on the Registry.

This issue will track the progress of the registry usage removal from SAML.

• Introduce persistence layer to store SAML configurations & refactor registry implementation to follow new persistence layer carbon-identity-framework#6239
• Introduce SAMLSSOPersistenceManagerFactory to switch between different persistence implementation carbon-identity-framework#6240
• Introduce JDBC based persistence for SAML
• Introduce on-demand migration to move from Registry to JDBC
• Introduce background residual data migration

Additional context
Registry removal parent issue,

• Remove carbon registry usages in IS #20001