Enforce Header for all Java Files

Separate Issue from https://github.com/checkstyle/eclipse-cs/issues/451 and https://github.com/checkstyle/eclipse-cs/issues/388 ,

This issue to agree on a header for eclipse-cs and update all the Java files with it.

I see a few different kinds like:
https://github.com/checkstyle/eclipse-cs/blob/84f1b6103c96c01928bc50470d57e661bbea2a21/net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/config/CheckConfigurationTester.java
https://github.com/checkstyle/eclipse-cs/blob/5b295acc79fd1bc37e38d9a2f06c01667c57ed29/net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/transformer/ctransformerclasses/WhitespaceAroundTransformer.java

Checkstyle has its own which looks very similar.
https://github.com/checkstyle/checkstyle/blob/master/config/java.header