Description
Reduce the number of jobs running after merging a Pull request.
Goal: avoid queue on Travis filling up.
Concerns mainly Page Builder with most jobs.
The setting to cancel / interrupt builds should be propagated to other repos.
Also the number of Jobs in Kernel should be at least discussed (w/ Andrzej).
Remarks: The table with time needed for setup per repo is being prepared apart from this task (Maciek).