Add ccache, so it can be used when rebuilding the testsuite from source
from a development branch. Ccache is not used by default.
Related: osmo-dev I800062d0379295a6905851db29e820ff16217653
Change-Id: I94d22b8da9f897974c5913b2a8138c653c215446
Add new containers based on debian-bookworm. Make some improvements
over the bullseye containers while at it:
* Remove sed for cversion.h, as the #error it is trying to replace is a
warning now so it is a no-op, and we use our own eclipse-titan package
instead of debian's package.
* Make apt commands consistent
* Move commands around to make better use of the cache
* Clone osmo-python-tests from gerrit instead of gitea and invalidate
cache when master changes
* Tweak comments
Related: OS#6057
Change-Id: I4415fcde6518bd26d1e2cb5785ddaf84ac2116b3
Oliver Smith