Migrate non-sensitive argocd config to gitops

[ACLay]

The entirity of our argocd kubernetes config is currently stored in the config repo, but we should be able to migrate the non-sensitive stuff out into this repo instead.

[ACLay]

BisAppSettings changes are in https://git.developers.facilities.rl.ac.uk/isisbusapps/BisAppSettings/pulls/905