Argocd Architecture Doc

Package Merge Request

Package Changes

Create argocd architecture documentation

Doc preview: https://repo1.dso.mil/platform-one/big-bang/bigbang/-/blob/argocd-architecture-doc/docs/understanding-bigbang/package-architecture/argocd.md

For Issue

Closes https://repo1.dso.mil/platform-one/big-bang/apps/core/argocd/-/issues/53