[internals] use intake catalogs for all data access

[jhamman]

As our data catalogs begin to catch up to the sprint of the last few weeks, we can migrate to using intake for data loading throughout carbonplan_forests/load. For example, the following lines

https://github.com/carbonplan/forests/blob/f7cb47cad2d3e999b94e7d2ab91955fd4cb71c56/carbonplan_forests/load/mtbs.py#L15-L29

should be rewritten as

mtbs = cat.mtbs.monthly_perims_raster.to_dask()

[freeman-lab]

i'm supportive! so long as we can still specify between different sources e.g. az / gs / local, what would that look like?

[jhamman]

Ah, yes. carbonplan/data@18eb7ee made it possible to specify the root URI via the CARBONPLAN_DATA environment variable. We'll have a few options for how to expose this to users in this repo. FWIW, both of our hubs specify the correct url (by default) for the cloud they run in. So we would just need to find a way to do that for local usage and/or a way to override the default.