Fork vendored Mapbox dependencies

[louwers]

These are dependencies of MapLibre Native.

• earcut.hpp
• eternal
• polylabel
• protozero
• vector-tile -> https://github.com/maplibre/mvt-cpp
• wagyu
• mapbox-gestures-android
• geojson-vt-cpp
• geojson-cpp
• geojson.hpp
• cheap-ruler-cpp
• jni.hpp
• geometry.hpp
• pixelmatch-cpp
• shelf-pack-cpp
• supercluster.hpp
• variant
• Optional

It is probably a good idea to fork them all so that we can easily make a fixes if we ever have to.

Protozero is used by Libosmium, Mapnik and OSRM. Maybe some other members of the open source community want to help maintain these libraries (although judging from the fact that they have not received updates for many years, I am not sure how much maintenance is needed).