(#6542) - add install, samples and out directories to .gitignore (#6543)
(#6542) - add install, samples and out directories to .gitignore (#6543)

* (#6542) - add install, samples and out directories to .gitignore

* (#6542) Added comments and modified paths to make it explicit that we are ignoring top-level directories

istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io,istio/istio.io