Remove '<skipAPIAnalysis>true</skipAPIAnalysis>' properties that are now
obsolete since the platform-build detects automatically if the API-check
should run or not.

If a pom.xml only defines properties, move them to build.properties.

Move specific configurations up into the project's root pom.xml to be
able to rely on the aggregator-pom generated by Tycho-pomless.
Only keep examples/pom.xml because 'examples' isn't one of Tycho's
default aggregator directory names.