Dockerlab

- templates
- [x] assemble Dockerfiles
- [x] with pre-built images
- [x] full Dockerfiles
- [x] build docker images to dockerhub
- matrix: https://docs.github.com/en/actions/using-jobs/using-a-matrix-for-your-jobs
- `max_parallel: 1` for sequential builds
- [x] pre-commit

- [x] implement the cli
- `new/init`: copy essential files into a new directory
- [x] github workflow