feat(clubs) Added better club swipe system. Added empty favicon.ico

Every club now has a list of mods. They can only swipe people for their club events.
At this moment no UI exists for adding a club mod. The only way to do this is to do it manually by going to Firebase and:
  1) Go to the specific club's node and under the node 'clubMods', put the PID as the key and true as the value
  2) Go to system_settings/accessLevels node and put the same PID/true pair under the 'isClubMod' node

Also added an empty favicon.ico in the root folder to prevent the Apache error log from being cluttered with 'no favicon found' errors.
Merge branch 'add-clubs-to-events'