Add a GeometryOps.jl extension for things like `polygonize`

[rafaqz]

So that these methods know about the dimensions and crs of the Raster.

We could also just add a hard dependency and start using apply and other useful things internally here.

I think its best that Rasters dependends on/extends GeometryOps, and not the other way around? @asinghvi17 @skygering ?

[asinghvi17]

Agreed!