WFLY-3705 read-resource recursive-depth has no effect

Logic implemented according to bevavioral tables

1) Recursive decision and value propagation is isolated
2) Attribute validators changed
3) ReadResourceHandler no longer manipulates its own validators, but uses the ones in the definition
4) ReadResourceDescriptionHandler had yet another version of recursion logic - fix that one as well
5) Update testsuite to check for, hopefully, all conditions

This is a forward-port of https://github.com/wildfly/wildfly/pull/6591

Arcadiy, I hope you don't mind; I squashed this down to 1 commit. I tried to retain the most substantive part of the commit messages.