Jux rebased: Implement a good part of the results of the JUX Workgroup and Code Sprints

This rebased pull-request implements most of the results of the JUX Workgroup and Code Sprints

The original branch was jux here, but during the merges from master, some changes didn't merge properly.

So we had to redo all merges, and a few haven't made it yet in this initial pull request. But a good part are here already.

Related tracker items are marked with [JUX] (#31858 - #31872) and crossreferences will be added next days.