galaxykit CLI already supports `user delete <name>` and `group delete <name>`,

implement the missing deletions:

• `collection delete <name> [<version>]` - collections and collection versions
• `namespace delete <name>` - namespaces
• `container delete <name>` - local and remote EE repositories
• container manifest deletion (`container-image delete <container/name> <tag | sha>`?)
• EE registry deletion (`registry delete <name>`?)

(once done, we can start using these in tests => AAH-1192)

(the repo is https://github.com/ansible/galaxykit , `pip install -e .` in that repo should ensure calling `galaxykit` runs the development version; `command.py` handles CLI parsing, then there are individual py files for each kind/model)
(don't forget about supporting `args.ignore` on exception, like the existing ones)
((would be nice to also support deleting by id/pk, but it's probably nicer to do that after adding param parsing for subcommands (and `--help` to list any params)))