[Meta] Move over existing extensions APIs to work across versions

[saratvemulapalli]

We've built bunch of APIs for extensions but they do not work across versions.
After opensearch-project/opensearch-sdk-java#338 design is completed we have to move over all APIs to the new design to support multiple versions.

APIs:

• ExtensionRequest : PR [Extensions] Moving ExtensionsRequest to use Protobuf #6960
  • REQUEST_EXTENSION_CLUSTER_STATE
  • REQUEST_EXTENSION_CLUSTER_SETTINGS
  • REQUEST_EXTENSION_REGISTER_REST_ACTIONS
  • REQUEST_EXTENSION_REGISTER_SETTINGS
  • REQUEST_EXTENSION_ENVIRONMENT_SETTINGS
  • REQUEST_EXTENSION_DEPENDENCY_INFORMATION
  • CREATE_COMPONENT
  • ON_INDEX_MODULE
  • GET_SETTINGS
• RegisterRestActionsRequest - Primitive: String [Extensions] Adding versioning support for registering Rest actions #7302
• RegisterTransportActionsRequest - Primitive: String [Extensions] Adding cross version support for registering Transport Actions #7403
• ExtensionHandleTransportRequest - Primitive : String, byte[] [Extensions] Moving transport action API to support cross versions #7468
• IndicesModuleRequest - Half baked removing the API.
• InitializeExtensionRequest - Custom Data type: DiscoveryNode

Documentation

• Documentation support for versioned APIs for SDK opensearch-sdk-java#642