Add list/describe command to CLI for SavedDatasets, StreamFeatureViews, & ValidationReferences.

tchughesiv

Is your feature request related to a problem? Please describe.
These object types can't currently be viewed via the CLI.

Describe the solution you'd like
We should add the capability to the CLI as it already exists in the registry API.

Additional context
Identical to other existing object types -
e.g.

% feast saved-datasets --help
Usage: feast saved-datasets [OPTIONS] COMMAND [ARGS]...

  Access saved datasets

Options:
  --help  Show this message and exit.

Commands:
  describe  Describe a saved dataset
  list      List all saved dataset