Remove Portlet-parent-pom from portlet templates

[Steffengreiner]

Is your feature request related to a problem? Please describe.

Because of circular dependencies, the parent-pom system will be deprecated in the future.
Currently both portlet templates(java & groovy) include the parent pom as a parent declaration in their pom.xml.
This leads to syncing problems between the qube template and newer portlets without the parent-pom inclusion.

Describe the solution you'd like

The portlet-parent-pom should be removed from the pom.xml and replaced with the least necessary dependencies for proper portlet running(These can be extracted from the portlet-parent-pom and added as seperate dependencies.)