ADR on using a sidecar for caching the git repo for API actions aka triangle pattern

[palemtnrider]

Our API server will need to clone the gitops repo, add a branch, commit changes, and push changesets to a git server. The clone will be the most expensive operation. Having a cache or reference repo that is local and kept up to date will enable much faster clones.

Create an ADR describing this approach.

https://github.com/kubernetes/git-sync Is a sidecar that we may be able to leverage.