Update the README file

[nicolaslevy]

Currently, the README does not reflect the current state of the project. For example, it mentions that the project can be tested on quic.video, but in reality, quic.video showcases the repository prior to the fork by Kixelated.

I believe the new README should:

• Mention that this repository is aligned with the IETF drafts of MoQ and include links to those drafts.
• Explain the system for tagging the different IETF drafts, in case someone wants to test a specific draft, like draft-04 of MoQ.
• Mention that this project can be tested alongside englishm/moq-rs.
• Provide instructions for setting up the development environment, suggesting and explaining how to start moq-rs.
• Explain the structure of the project, specifically noting that the library (lib) contains the player.
• Include instructions for building the player.

Any other ideas to include?

[JoaquinBCh]

@englishm I've updated the README in this PR. Please review it when you have a chance. Thank you!