Dataset from zarr

[ocefpaf]

Closes #884 and #672.

@benjwadams I had to squash the original 17 commits to make this manageable but I believe I got everything in.

PS: This implements checker for nczarr! Not pure zarr datasets. The latter would be easier to implement when we move away from netCDF files as the base for compliance checking.

[codecov]

Codecov Report

Attention: Patch coverage is 60.60606% with 26 lines in your changes are missing coverage. Please review.

Project coverage is 81.75%. Comparing base (6a006e4) to head (7704919).
Report is 1 commits behind head on develop.

Files	Patch %	Lines
compliance_checker/protocols/zarr.py	71.79%	6 Missing and 5 partials ⚠️
compliance_checker/protocols/netcdf.py	30.76%	4 Missing and 5 partials ⚠️
compliance_checker/protocols/opendap.py	50.00%	3 Missing and 1 partial ⚠️
compliance_checker/suite.py	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1071      +/-   ##
===========================================
- Coverage    81.92%   81.75%   -0.17%     
===========================================
  Files           24       25       +1     
  Lines         5172     5224      +52     
  Branches      1237     1253      +16     
===========================================
+ Hits          4237     4271      +34     
- Misses         634      644      +10     
- Partials       301      309       +8     

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[ocefpaf]

@benjwadams only 1 test is failing, TestCLI.test_nczarr_pass_through[local_file], with:

                                     Errors                                     
--------------------------------------------------------------------------------
§2.1 Filename
* Dataset path file:///home/filipe/Dropbox/pymodules/01-forks/IOOS/compliance-checker/compliance_checker/tests/data/trajectory.zarr#mode=nczarr,file must end with ".nc"

That is something we need to skip b/c zarr files are, in a way, against that rule.

BTW, I could not make the skip option work. Not sure that is going on...

I skipped two tests: check_filename b/c .zarr won't pass a name test for .nc, and check_coordinate_variables_strict_monotonicity b/c I believe that openSourcerer9000 original dataset has a real issue that we need to fix to run the tests.

With that said, this PR works 🎉 and is read for a review!