set up test environment

Add the following:

• should run tests for Java (include at least one unit test)
• should run tests for JavaScript (include at least one unit test)
• should run tests for Vue (include at least one unit test)
• should create coverage for Java and JavaScript and pick it up by SonarScanner
• remove all non-needed pom entries
• do not run any tests when "-DskipTests=true" was given