connection options instead of setting REDIS_HOST etc individually

Close #1986

This reverts commit 5135d609.

* Allow puma to listen Unix socket

* streaming: Show the whole listening address instead of the port

Port is not always appropriate (e.g. Unix socket)

* streaming: Close server before exiting

This change especially allows to remove Unix socket before exiting.

* Make sure we start at least one streaming worker, even if there's only one CPU and we're in production mode.

* Oops, let's make sure we're counting cpus right too.

* Add eslint to dev dependancies so it gets installed for the repo

yarn add --dev eslint babel-eslint eslint-plugin-reac

project specific version of eslint, you can globally install eslint-cli
if you want the global runtime, or add .bin to your path

* fix eslint errors about inconsitent returns

* eslint ignore the same as git ignore. allows for eslint .

* Add editorconfig file so everyones editor will be setup to follow the same standards

Refresh timelines when streaming API reconnects in the UI

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.