Modernize cmake

[orzechow]

Following KIT-MRT/arbitration_graphs#68, this cleans up the CMake setup.

[ll-nick]

Nice, thanks a lot for keeping things consistent and updating things here too!

I'll approve this already but could also update the README?

• We now have docker stages and services inside a single docker compose file
• We don't need the find command to run all tests but can use cmake and the test target
• The test output also look different but I would just remove that part

[orzechow]

I'll approve this already but could also update the README?

* We now have docker stages and services inside a single docker compose file
* We  don't need the `find` command to run all tests but can use cmake and the test target
* The test output also look different but I would just remove that part

Good catch!

See a01337b