Backport new inventory priorisation, software deletion API and log correction in 6.1
When correcting #12937, we added a priorisation rule for new inventory (in `incoming`) above update of already accepted one.
We also corrected log of inventory acceptation, which were never displayed and added an API to trigger software cleaning.
These things need to be backported in 6.1 (they should have been corrected in 6.1 and upmerged). It should be straightforward.
From that PR (https://github.com/Normation/rudder/pull/3472/files), it's all file BUT SoftwareIdFinder.scala