[7.1] Speeding up clustering testsuite

Attempt #2: Unfortunately master ~ 7.2 needs to wait for ISPN 5.2 upgrade.

Features

* 2x speed up -> clustering ts now runs in ~8 minutes
* introduced abstract cluster test significantly reducing repetitive code
* leveraging ARQ custom container mode
* no more starting and stopping on every test
* replaced system outs with logger
* less intermittent issues
* reenabled most tests
* disabled consistently failing tests