expose API surface for loading netcdf directly from a Buffer

[riastrad]

I currently have an application that downloads NetCDF data from S3 and then uses this library to read that data. Unfortunately, with the API surface that's currently exposed, I'm forced to save the data I have to disk first and then read it back into memory.

Obviously, this isn't the ideal workflow, since I already have the object in memory when downloading from S3. So it would be preferable if I could simply pass my buffer to a netcdf method (e.g. new netcdf4.fromBuffer(data)) and skip the disk entirely.

Based on the C-library's documentation, this is already implemented in NetCDF4 (source docs) and it should just be a question of adding new bindings to this library.

@parro-it any chance of implementing this in the future? I'm not very familiar with this repo's code, but I could also try to put a PR together (definitely the slower option) if you'd be willing to review & then make a new release after it was merged.