Adds a new QGIS processing provider for 3d algorithms, available
only when QGIS is built WITH_3D
Currently includes only a single algorithm for tesselating geometries,
which exposes the functionality of QgsTesselator to processing.
Like the native c++ algorithm provider, algorithms in the 3d
provider are transparently merged with the other QGIS providers
(i.e. they aren't separated into their own group)