(related to AAH-1190, AAH-1191; dependency of AAH-1192)

Add missing galaxykit commands identified in AAH-1192 as things we're triggering in the UI from unrelated tests:

• `user group remove <user> <group>` (corresponding `user group add` already exists)
• remote registry creation (`registry create <name> <url>`? - sync name deletion in with AAH-1190)
• remote container addition (`container remote create ...`? - sync optional params with AAH-1191)
• sync remote container (`container sync <name>`?) (might not be needed if we can sync on create, but nice to have anyway)

(and update AAH-1192 with the right command invocations where missing)