* [proto] add APIs to send and receive musig2 signing data
* [common] add serialization functions for nonces and signatures
* [application] implements tree signing
* fix: remove old debug logs
* [proto] cleaning
* [common] fix musig2.go
* [application] fixes and logs
* [interface] fix: stop forwarding 2 times the events
* [client] add musig2 support + sign the tree when joining a round
* [interface] add new APIs into permissions.go
* [application][proto] rework PingResponse (return all events type)
* [common] split SetKeys into 2 distinct methods
* [client] fixes according to musig2.go changes
* [sdk] support tree signing + new PingResponse
* [sdk] fixes
* [application] revert event channel type
* [application] use domain.RoundEvent as lastEvent type
* [application] remove IsCovenantLess
* comments
* [application] revert roundAborted changes
* [interface] remove bitcointree dependencie
* api-spec: move the api-spec to root and init go.mod
* go mod tidy
* move buf files in the root as well
* gh action for api-spec changes only
* gh action for api-spec on push and pr
