Add tagging/untagging for container repositories

[gerrod3]

Summary

Both types of container repositories can be tagged and untagged. Should the commands be grouped under a tag subcommand under repository or just added as two separate commands?

Examples

pulp container repository tag --repository foo --name "custom_tag" --digest "manifest_digest"
pulp container repository -t push untag --repository phoo --name "another_tag"

or

pulp container repository tag add --repository foo --name "custom_tag" --digest "manifest_digest"
pulp container repository -t push tag remove --repository phoo --name "another_tag"

or maybe it's common enough to warrant it's own subgroup in container commands

pulp container tag add --repository foo --name "custon_tag" --digest "manifest_digest"
pulp container tag remove --repository push:phoo --name "another_tag"
pulp container tag list --repository foo overlaps with content -t tag list and repository content list -t tag

Tell me which command structure would be preferred.

[lubosmj]

I am good with the first option.

[ipanova]

I'd go with option 1 since these are actions which are performed under the repository