Removing unnecessary Bootstrap files

With this we have a simple version of the chat with the new design. If we want to improve it to make it look like the proposals (LIVEOAK-657), I would need some help in the following: 
- A way to detect that initially there are no messages, and display the big icon + informative text
- A way to display the coloured circle alongside the name. We need to get the first letter from the name and display it. Also, it is important to keep the color the same for the same username.