Improve documentation

[remi-braun]

• Update Contributing page with building documentation section
• Add documentation about writing into BytesIO Allow rio.to_raster with a BytesIO object #668, solves also DOC: add section on writing files in docs #584 about writing raster in the cloud
• Add a page dedicated to the switch from rasterio to rioxarray, and notably equivalences between rasterio functions and rioxarray methods
• Add a page about GDAL configuration options Does rioxarray use internal GDAL config parameters? #693
• Add and initialize external courses toctree
  • Carpentries courses DOC: link geospatial-python course in the docs #279
  • Geospatial Python courses by Earth Lab at University of Colorado, Boulder

[remi-braun]

I tried to fix some open documentation issues and propagate some user questions.
This can of course be amended by anybody, it's more of a draft right now.

Other questions :

• do you want to switch to another sphinx them?
• do you want to switch to markdown files instead of rst?

[remi-braun]

For the rasterio / rioxarray equivalences, it could be great to explain why some attributes in rasterio are becoming methods when others don't (i.e. transform). It's to preserve the lazy evaluation inherited from xarray and not recomputing on the fly these attributes when changing the raster (i.e. cropping, reprojecting...)?

[snowman2]

I think removing xda. in this table would be clearer as xda is not defined.

Suggested change

	| blockxsize | ``xda.encoding["preferred_chunks"]["x"]`` |
	| blockxsize | ``encoding["preferred_chunks"]["x"]`` |

[remi-braun]

I tried but I think it makes things ambiguous between methods accessible from xarray, from teh accessor or functions directly from rioxarray. I'll define what xda and ds are

[snowman2]

Maybe making the property/function linked to the documentation would make it more clear.

[remi-braun]

I tried to link properties and functions tell me if it suits you

[remi-braun]

Now it's better

[snowman2]

This can help make it more clear it is used with rio accessor:

Suggested change

	| count | :attr:`rioxarray.rioxarray.XRasterBase.count` |
	| count | :attr:`rio.count <rioxarray.rioxarray.XRasterBase.count>` |

[remi-braun]

Yes superb idea, now it's better 👍