Add clustering support to GeoJson source

[ivovandongen]

Since starting on the android runtime style api #5610, Clustering support has been brought to core by @mourner in #5724.

Add support for it in the Android binding and a sample in the test app.

[ivovandongen]

Initial clustering support. Filters don't have the right effect yet (circles don't appear at all when filters are set).

[1ec5]

#5962 tracks the iOS/macOS equivalent to this work.

[ivovandongen]

Fix in #5978 also fixed filtering on geojson sources. Separated the test in a new activity for clarity.

cc @mourner

[ivovandongen]

[ivovandongen]

Merged