Read directly from cloud.

[valentina-s]

Add functionality and examples to read directly from the cloud.

[valentina-s]

A script which reads .evr files from the cloud and downloads them temporarily and reads them with echoregions:
https://github.com/uw-echospace/hake-labels/blob/2019/zarr/zarr_mask_generation_2019.py

[leewujung]

Check the functions from echopype util/io.py: there should be a few functions that you can use directly!

[ctuguinay]

Referencing, an issue that @leewujung #95, we want to change the name validate_path (in utils.io) function so that we can use the validate_path described in echopype verbatim.

[ctuguinay]

Also, as mentioned by @leewujung #95, there needs to be changes made to the check_file function:

Also I think the content of this function should be cleaned up (the logic and also to check filename extension properly with pathlib or properly extracting the .XXX part instead of endwith; pathlib does not work for cloud path last time I checked so maybe some simple re use or similar). Could you put this as a separate issue?