Updated functions accepting a cell type to allow `CellType` class.

[metasim]

@vpipkt We should fix this to accept the CellType class directly, and not have the user do cell_type_name.

Originally posted by @metasim in https://github.com/locationtech/rasterframes/pull/230/files

[vpipkt]

I've contributed to #230

I will add some more unit tests to it once that branch merges develop back in.

[vpipkt]

Fixed. and demonstrated in docs. could still use a unit test or two.