Add patch CLI parsing with clap

Changes:

• Rebase

Various fixes

Improve the initial draft

The non-exhaustive list of changes are:

• Follow the original copy of the rad patch command help
• Make MessageArgs a re-usable struct that converts to Message
• Restructure ReviewArgs and remove ReviewActionArgs – the conversion to the review::Operation was incorrect, so this was fixed. While I was at it, I also improved the grouping of those parameters, using some clap tricks.
• Ensured the diff of commands::patch is easier to read
• Added LabelArgs and AssignArgs so that we can mark them as required
• Hide the [no-]announce flags, and expose them through should_announce
• Removed some unused fields

Changes:

• Resolve TODOs
• Fixes to visibility

Review and rebase

Changes:

• Change formatting of (default: cwd) to [default: cwd]
• pub(super) for ReviewOptions

Rebase