Minor optimisations included.

This alarm is focus on keep only the minimal and usable set of bt5 installed, this helps on quick upgrades.

Relevant upgraders should be reincluded as constraints.

In case catalog and zodb is at a inconsistent state (after a backup restauration for example), this alarm can check if all security uids are well indexed.

Once a interaction is trigger after _setPredecessor don't propagate reindexation to invalidated software Instances.

i.e no single line of code in this entire repository can start supervisord implicitely if option is set.
In such case, the only way to start supervisord is to run slapos node supervisord explicitely.