Multiple python interpreters in dev container cause issues

[Donaim]

Our docker image is based on python:3.8, which includes two versions of python.
One comes from the underlying distribution, and another one from the image maintainers.

As a result, when python packages are install during docker build, they are not immediately visible to vscode.

[Donaim]

Simply removing the "incorrect" python binary fixes the problem.

[Donaim]

Removing the whole incorrect python3.9 package does not work because apt remove fails with a dependency related error.

[Donaim]

We hope that the cleaner solution will be available after we switch to a more recent python version, like python 3.12.

However, an outstanding issue with minimap is currently preventing us from upgrading.

[Donaim]

Another alternative is to configure virtualenv for MiCall as it seems that editors default to the python version set in the .venv/pyvenv.cfg.

This requires more investigation.

[Donaim]

Solved by upgrading to a new python version (#1167)

However this may come up again, as the python versions deviate inside the container.

Maybe we should base the container on generic "Debian" or "Ubuntu" instead of "python:whatever"