Fixes to docker-compose.yml

Most SMTP servers will only accept valid email address for sender. #766

* Removing --replSet rs0 which causes issue as described here: https://github.com/RocketChat/Rocket.Chat/issues/1472
* Updating the mongo database datadir location so that if somebody decides to use volumes in order to maintain state, it works. I'm guessing mongodb changed it's default location from "mongo" to "db" and nobody noticed.

Block user registration and services registration

fix typo in docker-compose.yml

Account box customizable items

api/info

This reverts commit df525d6d.

This reverts commit 93a971bb.

Update README.md