Dependabot does not have access to secrets, so skip building containers

* Removes Travis Integration and migrates to Github Actions
* Builds binaries in Dockerfile via MultiArch
* Adds a Release Process
* Drops support for ppc64le, s390x container builds (as golang-alpine3.14 does not
  contain builds for them)

* Move lintand test jobs to Github Actions

* Integrate the gofmt check into Makefile

* Extract version for gobgp, gorelease, gomoq