Change the "--selected-stations" option in the csv2obsoul command to
"--selected-stations-fpath". This is to make it more obvious that this
refers to a file path.

The old syntax using "--selected-stations" should still work though, as
argparse tries to match the options from passed abbreviations.

With a somewhat basic config/plugin usage for flake8 at the moment.

Update .pre-commit-config.yaml and .gitlab-ci.yml to use these new
configs.

Also, remove dep "pytest-rerunfailures", no longer needed.

Redundant with functionality provided by the "show" command, as "select"
already saves files that can be read later by "show". Leave these options
only to "cluster" command now.

To print all configs in use (including defaults) in TOML format.

To show the domain that the code is using.

This causes the code to re-read the input netatmo data for the parsed
DTGs and save accepted observations in OBSOUL files, one for each parsed
DTG.

Without changing any functionality.