Add Alumni to team page

* adds an 'alumni' and 'published' boolean to team members and board members so we have more flexibility in the admin interface in displaying
* template code is begging to be DRYer but can't think of how to reorganize right now without readability taking a hit, so I'm ok with it for now 

note  that after the migration, we should loop over existing database entries and manually set them to (alumni=False, published=True) because 1) during my local migration it wasn't saving the existing entries until I did it manually and 2) published default is false but we want existing entries to remain published.