Add nightly CI for running existing rattler-build tests on build packages

Since the migration to rattler-build/recipe v1, and adding tests in vinca, we are now bundling tests with packages itself, so it should be possible not only to run them while a package is built, but also post-deployment after the package was uploaded (see https://rattler.build/latest/testing/). This would permit to easily catch ABI regression such as https://github.com/RoboStack/ros-humble/issues/274 .

The basic logic could be something:

• Check which packages actually have tests (not sure if we can get this info from the conda channel directly, or we need to check https://github.com/RoboStack/ros-noetic/tree/main/tests, https://github.com/RoboStack/ros-humble/tree/main/tests and https://github.com/RoboStack/ros-jazzy/tree/main/tests .
• Download those packages, and run tests on them (not sure if rattler-build test has some facility for that). As part of this, we should make sure that the dependencies used are the latest one, and not some kind of locked dependencies
• If CI does not pass, report it somewhere (the default reporting logic in GitHub Actions is not really convenient, see https://github.com/orgs/community/discussions/43415

Beginne mit der Testdokumentation von rattler-build und den vorhandenen Testverzeichnissen in ros-noetic, ros-humble und ros-jazzy. Ermittle, wie Pakete mit Tests identifiziert, mit ihren aktuellen Abhängigkeiten heruntergeladen, die Tests nach der Bereitstellung ausgeführt und Fehler gemeldet werden können. Als erledigt gilt die Aufgabe, wenn ein nächtlicher Workflow diese Prüfungen durchführt und Fehler klar sichtbar macht.