Split buildEffektRelease into building an NPM package and building a GitHub release

[jiribenes]

buildEffektRelease as we have it is very restrictive, it cannot fathom the idea of a different source of the release than GitHub.
That's not entirely correct, we can also get the .tar.gz NPM package from NPM itself or from a custom build.

Therefore it might make sense to split buildEffektRelease into:

1. buildEffektNPM: takes a NPM package as a source and builds it (that's most of what buildEffektRelease does right now)
2. a thin wrapper buildEffektGitHubRelease (with a temp deprecated alias buildEffektRelease) which takes a version and hash, gets the .tar.gz file from GitHub Releases and calls buildEffektNPM

Feel free to come up with better / more idiomatic names.