cubicweb #1253628 be smarter about when to check RQLConstraints [open]

If my schema says:

A rel1 B
A rel2 C RQLConstraint('S rel1 B, B rel3 C')
B rel3 C

I can easily generate an inconsistent state because the RQLConstraint is only checked when rel2 is updated.

A smarter way of doing this would be a real timesaver when working with complex schemas. The smarter way is noticing that the constraint depends on re12 and rel1 and rel3, and therefore needs to be checked whenever any of these three relations is updated.

Constraints involving an attribute value also need to be enforced whenever the attribute value is updated.

done in<not specified>
closed by<not specified>