Websocket Support (#937)

* Atom / RSS meta link

* Spike

* Feeling good about this spike now

* Remove document.collection

* Remove koa.ctx from all presenters to make them portable outside requests

* Remove full serialized model from events
Move events.add to controllers for now, will eventually be in commands

* collections.create event
parentDocument -> parentDocumentId

* Fix up deprecated tests

* Fixed: Doc creation

* documents.move

* Handle collection deleted

* 💚

* Authorize room join requests

* Move starred data structure
Account for documents with no context on sockets

* Add socket.io-redis

* Add WEBSOCKETS_ENABLED env variable to disable websockets entirely for self hosted
New installations will default to true, existing installations to false

* 💚 No need for promise response here

* Reload notice

webpack.config.prod.js

@@ -38,6 +38,7 @@ productionWebpackConfig.plugins = [
     'process.env.NODE_ENV': JSON.stringify('production'),
     'process.env.GOOGLE_ANALYTICS_ID': JSON.stringify(process.env.GOOGLE_ANALYTICS_ID),
     'process.env.SUBDOMAINS_ENABLED': JSON.stringify(process.env.SUBDOMAINS_ENABLED === 'true'),
+    'process.env.WEBSOCKETS_ENABLED': JSON.stringify(process.env.WEBSOCKETS_ENABLED === 'true'),
   }),
 ];