Setting of locale in controller extracted to Localized concern,
the doorkeeper authorized applications controller moved under
custom namespace with inclusion of Localized, which resolves the
"it sometimes appears in a different random language" bug

Small addition in case people want email service options, sparkpost.com gives you 100k/mo free

This adds the ability to filter user signup with a whitelist
instead of or in addition to a blacklist.

Fixes #817

add support for reading S3 protocol from ENV
also add S3_HOSTNAME in .env.production.sample

Make the streaming API also handle websockets (because trying to get the browser EventSource interface to
work flawlessly was a nightmare). WARNING: This commit makes the web UI connect to the streaming API instead
of ActionCable like before. This means that if you are upgrading, you should set that up beforehand.