Inline all the app endpoints
Namespace the main Sinatra app
Extract stats into separate app
Extract static endpoints into separate app
Extract help endpoints into separate app
Extract account endpoints into separate app
Extract backdoor endpoint into separate app
Extract session endpoints into separate app
Extract random solution endpoint into separate app
Extract comment endpoints into separate app
Extract exercises endpoints into separate app
Delete unused admin endpoint
Extract metadata endpoints into separate app
Extract team endpoints into separate app
Extract user endpoints into separate app
Extract error endpoints into separate app
Merge branch 'refactor-app'

Reorganize all the endpoints in the application. It's still horribly ugly,
but it keeps things a bit more separate, and makes it easier to see where we
can collapse duplication.