Get rid of special jetty-ee*-web.xml files

We have custom configuration file for jetty in the WAR to set the maxFormContentSiz and maxFormKeys properties. It's quite annoying since we have to provide a different file for each version of jakarta ee.

But according to the documentation, those two properties can also be configured in a much more generic way in the web.xml, which sounds a lot better...

Another generic alternative would be to set that programmatically in Java, but then the question is should this remain configurable, in which case we need to discuss where that configuration should be indicated.