[WFLY-490] tests for permissions coverage and role mapping based on properties files

Hi Brian,

I've added few tests here. The one for permissions coverage is not that interesting, it merely asserts that the entire domain tree has some permissions defined (which should always be the case). The second one is more interesting, it excersises users2groups2roles mapping via the mgmt-*.properties files, together with runtime reconfiguration of the mapping. Once we have LDAP working (Darran said he's going to work on that this week), I will add a variant of this test for LDAP too.

What I'm not so sure about is how the role mapping test is executed. I decided to create another set of standalone*.xml files for the purpose of this test, and therefore also another Maven Surefire plugin execution. Maybe it's overkill, I'm not sure... but even if it's not needed for the .properties files tests, it's probably going to be needed for LDAP. Anyway, if you could suggest how to do that in a better way, I'd be glad.

Thanks!

LT