[SUGGESTION] Compatibility of classes packages with the locations of java files

Hello Chris,

In the generated projects, the locations of Java files are not consistent with the Java standard :

In the archetype
- the java classes are tagged with the $package variable
- in the archetype-metadata.xml file, the filesets are not defined with the 'packaged' attribute.
Therefore, for the EclipseColorTheme sample project:
- the java files are copied into 'org/aniszczyk/minerva'
- the classes are defined with the com.github.eclipsecolortheme package.

So, I propose:
- to delete the 3 levels 'org','aniszczyk','minerva'
- to update the definition of each fileset.

If  you accept, I can pull a request...