Re-enabled Integration tests for xtend-archetype

[LorenzoBettini]

Closes #2258

This also fixes the IT project, which was missing a required property

[cdietrich]

@LorenzoBettini i cannot really play around with this.
do we know this also will work with milestones and release builds?
this was a big problem back before the repo merge

[LorenzoBettini]

@cdietrich

such tests will not be executed during releasing, just like the other tests.

Integration tests for this project used to have 3 problems:

• as you had spotted yourself, Integration tests for xtend-archetype failing on jenkins #2258 (comment), the IT specification was missing the required argument javaVersion, fixed by this PR
• the IT needs maven.home, which I had already dealt with in the past both for GitHub Actions and Jenkins: it points to the Maven wrapper installation
• the IT tries to build the generated project, which relies on SNAPSHOT versions of our artifacts, this PR deals with that by first installing the needed artifacts in a local test Maven repository, as we already do in our Maven plugins ITs

So everything is fine now concerning the integration tests for the archetype (see the builds, including Jenkiins)

[github-actions]

Test Results

  6 461 files  +1    6 461 suites  +1   3h 22m 28s ⏱️ + 6m 21s
 43 239 tests +1   42 655 ✅ +1    584 💤 ±0   0 ❌ ±0 
170 253 runs  +6  167 905 ✅ +1  2 336 💤 ±0  12 ❌ +5 

Results for commit 6fc2ee3. ± Comparison against base commit 9361743.