Add webrtc transport multidim interop (#100)

* update interop rust test lib to use tokio

to allow us add the WebRTC transport test (which is only available with
the tokio runtime)
Clean up the test and update Cargo.toml to 0.2.0 to avoid conflicting with the older tests, and allow us to import lib.rs
on the rust-libp2p repo and have the master tests there.

* simplify build_builder function

* replace deprecated ping keepalive

with KeepAlive Behaviour

* add WebRTC support for rust tests

* add webrtc support on interop generator.

* fix typo on generators.ts

webrtc instead of webtransport.

* update rust test plans to use enums instead.

* update rust tests enum to match the ones by generator.ts

* fix webrtc testcases to have proper security and muxer.

* review: address suggestions:

- undo generator changes, let's do that later on
- don't parse muxer and sec protocol where we don't need it

* ident generator.ts.