Update GitLab Example Maven project

Problem to solve

Update example maven project so that it works "out of the box" with only updating the endpoints as necessary changes.

From customer:

The example maven project that you suggested, https://gitlab.com/gitlab-examples/maven/simple-maven-app, has no configuration to pull the simple-maven-dep in the pom.xml, and even cloning this to my machine and running mvn clean install it is unable to compile ~/simple-maven-app/src/main/java/com/example/app/App.java:[3,23] package com.example.dep does not exist (because it is not configured in pom.xml).

Source (internal): https://gitlab.zendesk.com/agent/tickets/127586

Further details

As the project endpoint is straightforward, updating this project to use group or instance endpoint would be a great added value.

Example project

Possible sample project to move over: https://gitlab.com/tpresa/maven-test

What does success look like, and how can we measure that?

Users can fork/clone the project as a working example.

Links / references

Edited by Tristan