Stub out feedback form

This adds a stubbed-out (non-functional) version of the feedback form demonstrated here: https://code.librehq.com/ots/clients/lfc/torque-tracker/-/issues/280#note_10573

Notes:

• Whether we actually log the feedback on the initial click (and just update it with any optional comment), or wait until the user actually confirms via "Submit" to store any feedback at all -- I leave up to you / the client to decide. (It was suggested that it should be the latter, because we were told feedback without a comment isn't useful.)
• The submit button currently does nothing. What it should do is submit the data, but it will also need to remove the open property from its parent details element. (See the inline JavaScript for the "Cancel" button to see how.)
• Strings are already internationalized

Closes ots/llm/meta#51 (closed)

Addresses but does not close https://code.librehq.com/ots/clients/lfc/torque-tracker/-/issues/280#note_10573