Finish README.md

[realcoloride]

The README.md file is incomplete for the 2.0 branch.

Roadmap:

• Finish unfinished parts
• Rework the call samples (linked to Fix livekit & audio dependencies #201)
• Change HTTP_AUTHORIZATION tutorial (linked to HTTP_AUTH Token has been moved into cookies #202)
• Ensure quality: check grammar and readability

[realcoloride]

I have noticed I have not added a section relating to how to close the connection / unauthenticate.

[realcoloride]

#202 Must be finished

[realcoloride]

Commit 2eda98c was done to fix #202