Generic Git Provider: deprecation path for GitOpsConfig

What do we need to do to deprecate the `GitOpsConfig`?

Make a plan for what will need to be removed from the code base when we deprecate GitOpsConfig fully.

Add `//Deprecated` godocs to the `GitOpsConfig` struct and find other places where it would be worth-while to surface deprecation warnings to useres.

Search the codebase for the GitOpsConfig struct and its other uses. Review how GitOpsConfig is exposed to users, then document the removals needed for full deprecation and add the requested //Deprecated Go documentation and any justified deprecation warnings. Done means the deprecation plan is recorded and the relevant user-facing surfaces are identified.

Written by the indexing model from the issue text.