Support for loading data from zarr Arrays

[sk1p]

Work in progress, just to keep track of things in flight.

Can possibly benefit from sharing some code with HDF5 DataSet. In addition, we could add a tensorstore backend.

TODO

• clean up: share more code with HDF5 DS, remove some copy-pasta
• add tests
• sync_offset and reshaping support, can possibly be added together with HDF5 (should be very similar!)
• add to list of supported formats at libertem.io.dataset
• possibly look into replacing our custom raw cache format with zarr arrays (per partition?) - probably via the nice tensorstore interface

Contributor Checklist:

• I have added or updated my entry in the creators.json file
• I have added a changelog entry for my contribution
• I have added/updated documentation for all user-facing changes
• I have added/updated test cases
• I have included the rebuilt production build of the client (only if changes were made to the GUI)

Reviewer Checklist:

• /azp run libertem.libertem-data passed

[codecov]

Codecov Report

Merging #997 (0aa4dcb) into master (346d433) will decrease coverage by 34.09%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           master     #997       +/-   ##
===========================================
- Coverage   68.87%   34.78%   -34.10%     
===========================================
  Files         260      261        +1     
  Lines       11977    12196      +219     
  Branches     1640     1667       +27     
===========================================
- Hits         8249     4242     -4007     
- Misses       3412     7748     +4336     
+ Partials      316      206      -110     

Impacted Files	Coverage Δ
src/libertem/io/dataset/base/tiling.py	79.06% <0.00%> (-10.51%)	⬇️
src/libertem/io/dataset/zarr_dataset.py	0.00% <0.00%> (ø)
src/libertem/io/dataset/base/coordinates.py	21.05% <0.00%> (-78.95%)	⬇️
src/libertem/io/utils.py	24.00% <0.00%> (-76.00%)	⬇️
src/libertem/analysis/radialfourier.py	23.07% <0.00%> (-74.62%)	⬇️
src/libertem/io/writers/base.py	24.19% <0.00%> (-74.20%)	⬇️
src/libertem/contrib/daskadapter.py	27.27% <0.00%> (-72.73%)	⬇️
...ertem/web/notebook_generator/notebook_generator.py	27.27% <0.00%> (-72.73%)	⬇️
src/libertem/masks.py	15.46% <0.00%> (-72.38%)	⬇️
src/libertem/web/generator.py	28.57% <0.00%> (-71.43%)	⬇️
... and 97 more

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[uellue]

@sivborg and @magnunor are using Zarr for their 4D STEM work with HyperSpy/pyxem, so this could perhaps be moved up in priority? :-)

Refs #1277

[matbryan52]

@sivborg and @magnunor are using Zarr for their 4D STEM work with HyperSpy/pyxem, so this could perhaps be moved up in priority? :-)

Refs #1277

If you like I could pick this up again?

[sk1p]

If you like I could pick this up again?

Sure, go ahead!