Make verification module usable as Eclipse cs extension

Since XCOMMONS-353 it's impossible to use our checkstyle configuration as it is in Eclipse cs because it cannot find the custom rule that has been added in it. The only way to support custom rule in Eclipse cs is to provide Eclipse plugin for it.

The idea is to make xwiki-commons-tool-verification-resources contain enough information to just be dropped as plugin in Eclipse to provide the custom rule (and the standard XWiki configuration as a bonus).