add cli options for config file management

[ltalirz]

fixes #30 fixes #8 fixes #13

Add cli option:

--testing-config-action: Read config file if present ('read'), require config file ('require') or generate new config file ('generate'). --regenerate-test-data: Regenerate test data

A few things left to do:

• [x] add docs
• [ ] use type hints more?

[ltalirz]

Just to point out that some strange stuff was going on with github actions (see e.g. the ci results of "add test for regeneration of test data").

Also, on my computer, the 4 tests that involve running the CalcJob fail with error messages

$ cd tests; pytest

...

    def check_diff_output(result):
        """
        Checks the result from a diff calculation against a reference.
        """
        diff_res_lines = tuple([
            line.strip() for line in result['diff'].get_content().splitlines() if line.strip()
        ])
>       assert diff_res_lines == (
            "1,2c1", "< Lorem ipsum dolor..", "<", "---",
            "> Please report to the ministry of silly walks."
        )
E       AssertionError: assert () == ('1,2c1', '< ...silly walks.')
E         Right contains 5 more items, first extra item: '1,2c1'
E         Use -v to get the full diff

(i.e. check_diff is empty for those). Haven't figured out why yet.

[ltalirz]

This seems to have been fixed by requiring the data directory to be an absolute path.

[ltalirz]

happy to add them in here, now that we've agreed on the names

[greschd]

fixes #30 fixes #8 fixes #13

Drei auf einen Streich! Nice 😄