Remove testing/wicket-arquillian from the sub-modules
Remove testing/wicket-arquillian from the sub-modules

It leads to build failures at BuildBot due to clashing ports. And slows down the build locally.
This way the code will stay in Git for anyone who wants to use it as inspiration, but since there is no special integration there is no chance to regress here.

(cherry picked from commit eb6b7f6ac58700c95de283c9bcbab4ee740d6060)

mosoft521/wicket,apache/wicket,apache/wicket,apache/wicket,mosoft521/wicket,apache/wicket,mosoft521/wicket,apache/wicket,mosoft521/wicket,mosoft521/wicket