Fix setup.py and added basic CI testing
This MR fixes a few notable things:
- the broken package_data in setup.py (you get an error with a modern setuptools)
- the use of cmmndeb_build_manager within setup.py introduces a condition whereby pip must have installed cmmndeb_build_manager before it can read the metadata about which dependencies it needs. pyproject.toml solves this problem.
- there is no CI on the repository, so we don't know if changes actually break anything
Initial tests for CI using centos:7 were not successful due to the requirement for a full compiler environment in order to install Jpype1, so I use the pre-compiled one from conda-forge (as well as their openjdk).