Global image for external

[judovana]

This PR is enabling any possible image to be fed to external tests. User can set it via EXTERNAL_AQA_IMAGE variable. Eg EXTERNAL_AQA_IMAGE=my.local.repo/on/hdd/fedora:40. Any legal subset -eg just fedora is allowed. The properties model was quite enhanced to work properly in multi distroenviroenment. This may be also good base for future localhost runs. I had tested all features on default ubuntu based temurin and on fedora:39. To tune it for centos/rhel will be quite a fun. But full tuning should not be part of this PR.

The build_all.sh is not affected by this change.

this is currently draft, becasue for some reasonnot yet found by me, the mounted jdk in fedora ... is not here. The default works. I wil continue to work on this, but any feedback appreciated.

Close #5555