test: add performance test workflow DHIS2-20175

[teleivo]

• add independent Maven module dhis-test-performance were we are going to put our Gatling performance tests into. @enricocolasante will start adding one in org.hisp.dhis.test.tracker
• add workflow .github/workflows/run-performance-tests.yml to compare 2 versions
• the workflow can be manually triggered using the GitHub CLI. See .github/workflows/run-performance-tests.yml for how
• the workflow runs the tests in Docker on our self-hosted performance test runner. Only one workflow run will run at a time so runs don't influence each other
• Gatling HTML reports and a simulation.csv extracted from the binary simulation.log is uploaded. These artifacts are kept for 90 days.
• run summary describes the test environment, the artifacts and how to get them. Example
  https://github.com/dhis2/dhis2-core/actions/runs/18009761816

Next

• @enricocolasante will add a test relating to tracker events
• I'll look into if we can speed up the DB setup. I already create a DB image using the restored dump so the comparison run can use the cached image. Subsequent runs also benefit from this. That first creation is still rather slow though.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[ameenhere]

Very nice start @teleivo !