ensure that cgroup cleanup does not hang indefinitely

[luxe]

There appears to be two potential infinite loops during cgroups cleanup:
In the controller: while (exists) {...} In the group: while (!killAllProcs(controllerName))

We leave the implementation as-is, but ensure that the closing of the controller does not exceed 10 seconds. This means we will provide a best effort cleanup for cgroup procs, but not hang indefinitely in the above mentioned cases become stuck.

Additional logging is added to see if these timeouts occur.