Slow network speeds when communicating via TURN server

[mbfm]

We currently experience very slow network speeds when communication is relayed by the TURN server.

This may be caused by #270.

[mbfm]

NetBird has integrated a new WebSocket-based implementation for the relay, which may resolve this problem (and would also be preferable for firewall clearances, since it only needs Port 443): https://netbird.io/knowledge-hub/october-newsletter

Tasks:

• [ ] Update https://github.com/eclipse-opendut/netbird-fork to the newest commit from the official NetBird repository
  • Merge the Protobuf file with the additional MTU field. Make sure to increment the number for the MTU field, so there are no conflicts.
• [ ] Update https://github.com/eclipse-opendut/netbird-build by looking at the GitHub workflows in the official NetBird repository
• [ ] Increment the NetBird versions in the openDuT repository
• [ ] Add the new relay server to the LocalEnv and TestEnv deployment code.
• [ ] Check the docker-compose file in the official NetBird repository for changes compared to our LocalEnv/TestEnv docker-compose file.
• [ ] Remove coturn from the openDuT deployment code.

[mplicht]

Version update done by story #378