feat(argocd): implement manager (#9771)

lib/manager/api.ts

lib/manager/argocd/__fixtures__/malformedApplications.yml

lib/manager/argocd/__fixtures__/randomManifest.yml

lib/manager/argocd/__fixtures__/validApplication.yml

lib/manager/argocd/__snapshots__/extract.spec.ts.snap

lib/manager/argocd/extract.spec.ts

lib/manager/argocd/extract.ts

lib/manager/argocd/index.ts

lib/manager/argocd/readme.md

lib/manager/argocd/types.ts

lib/manager/argocd/util.ts