Buildout cannot request destroy sub instances when it is removed from
instance parameters by the user. Ex: request a cluster of KVM, with
kvm1 and kvm2 instances, edit parameters and remove kvm2 in the list.
Buildout will just ignore that instance and it will be removed only when
the hosting subscription will be destroyed.

                 -- kvm1
root instance --|
                 -X- kvm2

So when processing a partition, we send to master the list of requested sub
instance(s). If the previous list was ['kvm1', 'kvm2'], then after remove kvm2
the list will be ['kvm1'] (for the root instance). Commit this list to the
master will unlink between root instance and kvm2 (predecessor categorie).

A new alarm will search for unlinked instances: Instance which has no parent,
and destroy them (also destroy the sub tree).

slapos_monitoring: create jio_storage only once for each storage and update when configuration change

Change allocation scope to close/outdated

monitoring_rjs_unsafe website for tests which allow ajax on local test http server
Add missing option on local http server
fix start of http server (address already in use)