New tests and DOJO_WORK variables

[tomzo]

• added e2e tests on alpine and ubuntu18, executed in inception-dojo image
• ported tests to pytest, dropped bats which does not work on alpine
• export DOJO_WORK_* variables for all started processes #17391
• added script to image_scripts which always setups /run/user/<ID>

[xmik]

Approved :) Please merge onto the private git server, so that it is tested before pushing to github and so that github release works.