UI/UX Improvements

[ezrichards]

• Add a "delete meeting" button to the admin page
• Make it clearer that feedback is optional in the attendance form (could even make a toggle for the field or a button that opens it if people do want to give feedback)
• Profile pictures are kind of scuffed/stretched in the "about us" page (profile page seems fine so we just need to replicate this logic)

[ezrichards]

Delete meeting button should probably have a confirmation modal/dialog, and the last DB migration also duplicated things so we need to clear duplicate previous meetings via either the DB or this new feature (which would be easier).

A plus would also be the meetings list being paginated - the scrollable text area is kind of massive, and we often don't need to see meetings back to the start of ACM.

[ezrichards]

Fixed in #69