… BOs

Features:

- new base oscillation types:
  - cosine
  - square
  - sawtooth
  - dirichlet
  - mls (maximum length sequence)
- new Python API (gutenTAG.api) with support for BO generation

Development improvements:

- refactoring of base oscillation and anomaly kind classes
- infrastructure move to GitHub #7
- automatically update GitHub Actions #16