Extension migration example - deprecate console feature flag extension in favor of core feature flag extension

OCP Console Dynamic Plugin SDK is released as of 4.12. In order to meet our API service guarantee, we cannot immediately remove console extensions. Instead we need to favor a deprecation model to give plugins time to adopt the new extension types.

AC

• Deprecate console feature flag extension in favor of core feature flag as an example
• Solution in place for how deprecations should be communicated and followed up on