fixed default facets for depended "java" projects

What did I do:
* only "fixed" facets are senseless as they have no effect at all such that I added "installed" facets instead
* "jst.web" and "jst.utility" are not allowed together and not required for an "war" depended "java" project
* "jst.utility" requires "jst.java"
* adjusted tests accordingly to the above statements

This was already discussed in http://gradle.1045684.n5.nabble.com/Default-configurations-for-Eclipse-WTP-plugin-on-dependent-jar-td5713163.html (first question and answer)

This is just a first small improvement to the "eclipse-wtp" plugin and I haven't found a dedicated issues. But I would like to fix some more of https://issues.gradle.org/browse/GRADLE-2186?jql=status%20in%20%28Open%2C%20Reopened%29%20AND%20text%20~%20%22eclipse-wtp%22 in some further pull requests ... unfortunately nobody answers to the above gradle-dev question any more (as I have already prepared a lot more changes to the ```EclipseWtpPlugin``` ...)
just figured out, that "jst.web" and "jst.utility" are both in the groups "modules" and are therefore conflicting ...