Download data directly into memory

[jtanwk]

Is your feature request related to a problem? Please describe.
Currently, modis_tools only downloads raw MODIS files to disk. There are use cases where you don't want to use modis_tools only for downloading, but instead as part of a larger application that uses modis_tools to retrieve data on an ad-hoc basis.

Describe the solution you'd like
The ability to download selected MODIS product tiles directly into a spatial data object in memory without writing to disk. This could be an xarray.Dataset, a rasterio.DatasetReader, etc. This removes the need to do manual cleanup post-hoc.

Describe alternatives you've considered
Adding code to clear the downloaded files manually, but this is less flexible.

Additional context
N/A