test: merged protocols

[lchenut]

Combined Protocols for WebRTC-Direct Testing

This PR merges all the individual protocol implementations (UDP, STUN, DTLS, SCTP, and DataChannel) into a single branch for testing purposes. Its primary goal is to enable testing and validation of the WebRTC-Direct transport.

Context

• Merged Protocols:
  • UDP, STUN, DTLS: Fully implemented, reviewed, and merged into the main branch.
  • SCTP: Implementation complete and partially reviewed, but not yet merged.
  • DataChannel: Implementation complete, pending review and merge.
• This PR combines all the protocols into a single branch to streamline integration testing. It is not meant to be merged into the main branch but rather serves as a temporary solution to test WebRTC-Direct functionality end-to-end.

Notes

• Do not merge this PR into the main branch.
• Some changes done here are fixes to bugs discovered while trying to make the end-to-end work, it will be necessary to cherry-pick those.
• Continue reviewing and merging SCTP and DataChannel implementations individually.