Switch to archetype plugin 3.4.1, avoid false warning when creating project from archetype

[WolfgangHG]

I think I finally found a workaround to resolve the warning from #51 and switch to recent versions of the maven archetype plugin.

In "archetype-metadata.xml" I had defined fileSets for e.g. "src/test/java" or "src/main/webapp", and those directories also contained java files files or deployment descriptors:

        <module id="web" dir="web" name="web">
            <fileSets>
                ...
                <fileSet encoding="UTF-8" packaged="true" filtered="true">
                    <directory>src/test/java</directory>
                </fileSet>
                <fileSet encoding="UTF-8">
                    <directory>src/main/webapp</directory>
                </fileSet>
                ...
            </fileSets>
        </module>

This caused the warnings.

My workaround: I added a "includes" filter for all those directories:

        <module id="web" dir="web" name="web">
            <fileSets>
                ..
                <fileSet encoding="UTF-8" packaged="true" filtered="true">
                    <directory>src/test/java</directory>
                    <includes>
                        <include>**/*.java</include>
                    </includes>
                </fileSet>
                <fileSet encoding="UTF-8">
                    <directory>src/main/webapp</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </fileSet>
                ...
            </fileSets>
        </module>

Now the warning is gone. Feels like a hack...

This commit supersedes #180
Also, in the subsystem archetype, there was a fileSet definition copied from one of the other archetypes, I removed it.