Computer Partition should acquire region from parent.

Conflicts:
	bt5/erp5_base/bt/revision
Acquire subordination from parent Computer.

Thanks to this Computer Partitions can be in same category as Computers they
are contained in.

Conflicts:
	bt5/erp5_base/bt/revision
Add group acquisition on Computer Partition

Conflicts:
	bt5/erp5_base/bt/revision