Enforce generic dependencyversions through cms7-project pom dependency management

Several generic dependencies like xerces, xalan, xml-apis, commons-logging, etc. should be predefined on cms7-project level such that all child projects use (at least) those versions or scope.

Specifically:

• as predefined dependencies (not dependency management!) with scope "provided" to excluded them from (war) bundling:
• xml-apis
• commons-logging
• as dependency management configuration to pin their version and/or provide them as predefined:
• xercesImpl (at least): 2.9.1
• xalan (at least): 2.7.1
• geronimo-jta_1.1_spec: 1.1

Concerning transitive javax.transaction:jta dependencies: these should be excluded everywhere from any cms7 project (as we'll depend on/use geronimo-jta only)