* 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

* introduce go.work and remove all replaces

* solve dependencies and force btcd/btcec@v2.3.3

* go work sync

* force btcd/btcec@v2.3.3

* go mod tidy