Determine version with versioningit tool

This tool is similar to the setuptools-scm
but offers more configuration options which
were required in the hivemind use case.

Needed:
- File-based versioning (write to file)
- Substitutions (commit sha)
- Substitutions (commit timestamp)

Good comparison is available here:
https://setuptools-git-versioning.readthedocs.io/en/latest/differences.html