Add dependency freeze file
This adds
- a requirements.txt file built from the dependencies of the cki packages installed via GITLAB_COM_PACKAGES
- a GitLab job verify-freeze-file (that is currently allowed to fail) that will check whether the version-less package list in the freeze file is the same as a rebuilt package list via the mechanism above
With these pieces in place, it should be possible to setup a renovate job that will keep the freeze file up to date.
Note that currently this does not affect the package installation in the venv in any way.
Part of #59 (closed)
Edited by Michael Hofmann