Support Apple Associated Domain

[Manav Gabhawala]

The old MHacks website supported apple associated domains which helped with autofilling passwords on the app.

Re-add support for https://mhacks.org/apple-app-site-association and https://staging.mhacks.org/apple-app-site-association returning this JSON:

{
   "webcredentials": 
    {
     "apps": ["478C74MJ7T.com.MPowered.MHacks"]
     }
}