Add Github Actions to build binaries and releases for version tags

[9er]

When a new version tag is created, Github Actions can automatically build binaries and create a release.

The release workflow of bwNetFlow/flowpipeline seems like a good template to start from.

For now it only makes sense to build cmd/routeinfo_server. Running the tests should be added later, because currently they only run some benchmarks that require a config file and BGP session where the RIB is filled from.