add cloud storage support for annotations

[bkmartinjr]

This PR is a re-codification of #2501, resolving a number of issues with that PR. Many thanks to @arogozhnikov for the idea and draft PR.

Reviewers:
Functional: @seve
Readability: @seve

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Changes

• Port gene set and label annotation read/write routes to use DataLocator and the underlying fsspec package.
• In support of this, add a couple of new API surfaces to DataLocator
• Incorporate a couple of minor bug fixes noted in the original PR (eg, missing argument in annotations.py:write_gene_sets())
• Reformatting to current conventions

[codecov]

Codecov Report

Merging #2512 (ea6a4b9) into main (002c9a5) will increase coverage by 0.02%.
The diff coverage is 50.94%.

@@            Coverage Diff             @@
##             main    #2512      +/-   ##
==========================================
+ Coverage   71.61%   71.64%   +0.02%     
==========================================
  Files          94       94              
  Lines        6454     6464      +10     
  Branches      739      738       -1     
==========================================
+ Hits         4622     4631       +9     
- Misses       1756     1757       +1     
  Partials       76       76              

Flag	Coverage Δ
frontend	71.64% <50.94%> (+0.02%)	⬆️
javascript	71.64% <50.94%> (+0.02%)	⬆️
smokeTest	?
smokeTestAnnotations	?
unitTest	71.64% <50.94%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/common/annotations/annotations.py	63.82% <ø> (ø)
server/common/annotations/local_file_csv.py	51.41% <47.91%> (+1.41%)	⬆️
server/common/utils/data_locator.py	70.00% <80.00%> (+1.46%)	⬆️

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