WIP: Add ZarrTIFFWSIReader class.

[aacic]

The ZarrTIFFWSIReader reads fsspec json file which represents SVS wsi.
The methods: read_rect, read_bounds, _canonical_shape are copied from TIFFWSIReader, and it needs to be improved by introducing delegates or some other way.

The method infor reads SVS metadata which is stored in the root group metadata like:

{
  ".zattrs": {
    "multiscales": [
      {
        "metadata": {
          "objective_power": 40,
          "vendor": "Aperio",
          "mpp": [0.2525, 0.2525]	
        }
      }
    ]
  }
}

To test, execute from the root dir:

pip install -r requirements/requirements_dev.txt
mkdir -p samples/slides
mkdir -p samples/fsspec
cd samples/slides
curl -C - -o TCGA-22-1017-01Z-00-DX1.9562FE79-A261-42D3-B394-F3E0E2FF7DDA.svs   https://api.gdc.cancer.gov/data/73c69d24-6f9e-44e2-bfe5-a608d4cf5c27
cd ../../tests/zarrtiff/
python tiff_fsspec.py "../../samples/slides/TCGA-22-1017-01Z-00-DX1.9562FE79-A261-42D3-B394-F3E0E2FF7DDA.svs"  "../../samples/fsspec/73c69d24-6f9e-44e2-bfe5-a608d4cf5c27_fsspec.json" "https://api.gdc.cancer.gov/data/73c69d24-6f9e-44e2-bfe5-a608d4cf5c27"

Change the svs variable inside of tileserver.py to:

svs = "../../samples/fsspec/73c69d24-6f9e-44e2-bfe5-a608d4cf5c27_fsspec.json"

python tileserver.py

Open http://127.0.0.1:5000/ and verify how it works.

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Codecov Report

Attention: Patch coverage is 16.90141% with 59 lines in your changes missing coverage. Please review.

Project coverage is 99.23%. Comparing base (8ff4f5e) to head (9276647).

Files with missing lines	Patch %	Lines
tiatoolbox/wsicore/wsireader.py	16.90%	58 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #897      +/-   ##
===========================================
- Coverage    99.90%   99.23%   -0.68%     
===========================================
  Files           69       69              
  Lines         8715     8786      +71     
  Branches      1149     1160      +11     
===========================================
+ Hits          8707     8719      +12     
- Misses           3       61      +58     
- Partials         5        6       +1     

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[shaneahmed]

Add a link to tiff-fsspec generator file.

[shaneahmed]

Please change to appropriate name e.g., fsspecWSIReader.

[shaneahmed]

Add some documentation / introduction about the fsspec / json files.