Add downstream project integration in a seperate test module

[tobrun]

This PR adds integration of the downstream project mapbox-android-navigation. To limit breaking the actual test app, I introduced a separate module to host the navigation tests.

The reason for doing this is to

• be able to symbolicate native crashes that navigation/llp produces (eg. Native crash from LocationLayerPlugin #11843)
• be able to verify and test the downstream dependency integration before a final release

Another approach would be to integrate mapbox-gl-native as a submodule in the downstream project.

@danesfeder for now I copied over NavigationMapRouteActivity.java. Lmk if you would like to see a different setup.

cc @mapbox/android

[zugaldia]

Another approach would be to integrate mapbox-gl-native as a submodule in the downstream project.

[tobrun]

With new QA policy in place, this should be sufficient to catch regressions early