web UI for hat doffing

[pushcx]

Lobsters has hats so users can comment on behalf of projects. Unfortunately there's no web UI for doffing a hat so it's no longer usable.

For this ticket, add a "doff" link next to each hat on someone's profile (similar to the "disconnect" link for github/mastodon on /settings). The link should go to a form with one text entry to use as the "reason" message in Hat#doff_by_user_with_reason.
The link and form should only be visible/usable by that user and mods.