#177: updated maven to new parent

[hohwille]

• Switch to new maven-parent #177: updated maven config
• also fixed some leftovers that had been wrong from the start in oasp4j/devon4j

[hohwille]

So I am not using the new parent POM in the loplevel POM of the maven archetype because:

• projects should have 100% freedom to adopt their versions and settings for maven
• projects should not inherit github specific settings such as scm, issueManagement, etc.
• projects should not inherit Apache Software License 2.0 from devonfw.

However, we might also use the occasion to revisit the archetype parent POM and align this with our new maven parent (versions of plugins, etc.). We could even consider #118 and expose versions for all plugins in our maven-parent pom in a next release and reuse exactly these versions for archetype parent.
WDYT?