RFPL-2752:Metamer: add backward compatibility profile for WFK

Since there are some problems with WFK dependencies (at least metamer.war) it would be easier run tests without care about dep. using maven, and just use ones from somewhere on filesystem prepared before run tests.
New maven property "metamer.wfk.dependencies.dir" introduced, which has to point to dir where metamer.war and richfaces jars are placed. It requires no jars containing here if they cannot be copied into metamer's WEB-INF/lib folder.