Make the server easier to use for other hunts

[dlareau]

The focus of this project will always be PuzzlehuntCMU, and they will get the major voice on all features, but this codebase has started to see use by other puzzlehunts. Below is a list of things that should be done to make this project easier to use for non PuzzlehuntCMU hunts. (while keeping functionality the same for PuzzlehuntCMU)

• [x] Add file upload button for PDFs and resources (not everyone uses web hosted files)
• [ ] Make the google analytics code only show up on PuzzlehuntCMU's site (special non-tracked template?)
• [ ] Make all instances of the text "PuzzlehuntCMU" reference the settings.SITE_TITLE variable (Notably in password reset templates)
• [ ] Make a setting for which page users get redirected to after login
• [ ] Make a setting that allows for single player hunts (Clicking register silently creates a single person team in the background) (Maybe make this automatically happen when the team size is 1?)
• [ ] Make a setting for which features are enabled (Unlockables, chat, etc...)
• [ ] Give included static files more generic names (e.g. phcmulogo.png => logo.png)
• [ ] Make a setting for which features users/teams should have, not everyone needs the "allergies" and "location" settings (Maybe just incorporate a lot of things into a "local" vs "remote" setting)
• [ ] Add documentation for all of the above settings/features

I'm sure I will think of more as I'm implementing the above. I hope to include many of these in the v4.1 update that will hopefully come out some time this summer.