scale back site functionality + this years chores

[pinwheeeel]

• Remove is_open and applications_open for Organization model
• Get rid of "join" feature for clubs (show_members) -> maybe repurpose it to a "follow" button to keep up with announcements?
• Multiple owners for clubs
• Remove Courses model in favour of regular strings
• Reimplement day schedule/timetable format system (and allow events to be "all_day" to match google calendar)
• Remove comments for posts
• Move away from using Mapbox for the school map (maybe)
• any api changes resulting from any of the above
  more TBD