Remove dependency to 'n42org/tox:3.4.0'

Current Status

n42org/tox:3.4.0 is used to build the documentation.

Problems:

• setup does not work with docker in docker
  • 'make docs' results in "ERROR: tox config file not found" #4132
• this software is unmaintained (see https://github.com/n42org/docker-tox)
• not very clear who the publisher is
  • (https://github.com/n42org)
  • https://registry.hub.docker.com/u/n42org
  • https://n42.org/

Expected

tox is called more directly, without the need for n42org.

docker in docker should work (e.g. when creating multiple containers with different setups, edited via e.g. VSCode Container mode)

Solution

Execute tox directly, should be just a few cli steps within the makefile

Please let us know if you plan to work on this.

Yes!

[Sayalikukkar]

@kgoncharov , Can I start work on this issue.

[denyeart]

@Sayalikukkar go ahead and start since the issue has been open a long time, we'd appreciate a pull request. Thanks!