1. Builds arm and riscv images on arm as it is faster
2. Completely restructure the test suite
   a) so far, it was a convoluted mess from bash scripts building a python test image which used bash scripts to build the docker-image within itself and run the test in this docker-in-docker container
   b) now we use tox to build the docker-container and run the tests locally/CI
   c) we have support for all platforms docker supports
   d) much less code and less convoluted
   e) the pytest's conftest.py was cleaned up a lot
   f) one major cause for the random failures we've seen previously on the emulated platforms was due to using pytest-xdist and running the tests in parallel - this is removed now
   g) another issue I observed was a timing issues, esp. on RISCV. Adding some sleep commands before running the test commands fixed those.
   h) I added a test that compares the value of the CIPLATFORM var to the arch reported by FTL

Supersedes #1843