read support for ProdML

[d-chambers]

Description

This adds read support for ProdML (version 2.0 and 2.1), the file format used by Silixa's iDAS series and probably others. More info about the format can be found here.

@ahmadtourei - Could you please test this branch on your Silixa data to see what issues you run into? I imagine there are some edge cases I haven't account for yet.

@rwporritt - It would be great if you could also test this branch on some of your datasets.

Related issues: #121, #152

Side note: of all the HDF5 formats we currently support, this one would probably be easiest to implement write support, but that will have to be a different PR.

Checklist

I have (if applicable):

• referenced the GitHub issue this PR closes.
• documented the new feature with docstrings or appropriate doc page.
• included a test. See testing guidelines.
• your name has been added to the contributors page (docs/contributors.md).
• added the "ready_for_review" tag once the PR is ready to be reviewed.

[codecov]

Codecov Report

Merging #157 (54ddd77) into master (72b31e2) will increase coverage by 0.19%.
The diff coverage is 99.37%.

@@            Coverage Diff             @@
##           master     #157      +/-   ##
==========================================
+ Coverage   96.62%   96.82%   +0.19%     
==========================================
  Files          55       58       +3     
  Lines        3436     3589     +153     
==========================================
+ Hits         3320     3475     +155     
+ Misses        116      114       -2     

Flag	Coverage Δ
unittests	96.82% <99.37%> (+0.19%)	⬆️

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

Impacted Files	Coverage Δ
dascore/utils/misc.py	98.74% <96.66%> (+1.06%)	⬆️
dascore/constants.py	100.00% <100.00%> (ø)
dascore/core/patch.py	98.41% <100.00%> (+0.02%)	⬆️
dascore/core/schema.py	100.00% <100.00%> (ø)
dascore/io/core.py	95.60% <100.00%> (ø)
dascore/io/prodml/__init__.py	100.00% <100.00%> (ø)
dascore/io/prodml/core.py	100.00% <100.00%> (ø)
dascore/io/prodml/utils.py	100.00% <100.00%> (ø)
dascore/utils/pd.py	97.92% <100.00%> (+0.05%)	⬆️

... and 1 file with indirect coverage changes

[d-chambers]

I need some of these changes for another branch I am working on, so I am going to merge for now. @ahmadtourei and @rwporritt if you get time to test this and find any issues please open an issue/PR so we can fix it before the next release (probably around June 20th).

[rwporritt]

Sorry, still new to team work on github. More specifically, I need to download this branch and test if the new IO codes work on my data?

[d-chambers]

No worries. Here is the gist of it, but let me know if anything isn't clear.