Create template/archetype for OASP4J+OASP4JS

[hohwille]

We offer OASP4J to create backend apps written in Java. Therefore we offer a maven archetype as template for such project.
We also offer OASP4JS to create frontend apps written in TypeScript and Angular. There are many projects that want to combine both. Therefore I see two general options:

• create and develop frontend and backend almost completely independent of each other. Also the frontend will come with its own webserver and therefore both frontend and backend are released and deployed separately.
• create an integrated project with a build that triggers both frontend and backend. In that case it is also possible to have the frontend build artifact directly embedded into the backend build artefact (war file).

MTS is going for the first approach.
This issue is about supporting projects that want to go for the second approach. In Java maven is the recommended build-system. Using frontend-maven-plugin (https://github.com/eirslett/frontend-maven-plugin/) the frontend build (with npm, yarn, gulp, etc.) can easily be integrated.

A new template should be created in oasp4j that can be used for this option and already ships with such build process and is based on the latest "oasp4j-standlone" template and the latest "oasp4js-template" (ng-project-seed).

This ticket is a replacement for #586 that I am going to close.