Remove CLIRR + japicmp from the build

Since we need only one tool to check our backward compatibility we should remove CLIRR and japicmp if revapi proves to work fine. ATM revapi is enable but CLIRR and japicmp are available by running;

mvn ... -Dxwiki.japicmp.skip=false -Dxwiki.clirr.skip=false

In order to verify revapi works fine let's compare the violations reported by CLIRR and revapi during releases for a few releases.