Draft: Add Python modules needed by custom signing as runtime dependencies
Using the KDE signing service via a custom signing command requires adding some Python modules to the Python provided by Craft. This MR adds the needed modules. Two are/were already in the KDE blueprints, i.e. they will have to be removed there.
I'm using the following custom signing command
python C:/Gitlab/Craft/ci-notary-service/signwindowsbinaries.py [...]
which causes the Python which is provided by Craft to be used.
A different approach would probably be to add an explicit path for the Python that is provided by the system (and which does already provide the needed modules). I guess that's a better solution. I'll give this a try.