IO updates, new StacApiIO class

[matthewhanson]

Related Issue(s): #
#61 #62

Description:

• Client updates to utilize PySTAC's new StacIo class. A new StacApiIO class is created, inheriting from DefaultStacIO.
• Refactor conformance classes

PR Checklist:

• Code is formatted
• Tests pass
• Changes are added to the CHANGELOG

[codecov-commenter]

Codecov Report

Merging #60 (124a0e6) into main (ee54486) will decrease coverage by 2.56%.
The diff coverage is 90.05%.

@@            Coverage Diff             @@
##             main      #60      +/-   ##
==========================================
- Coverage   85.23%   82.66%   -2.57%     
==========================================
  Files          13        8       -5     
  Lines         630      427     -203     
==========================================
- Hits          537      353     -184     
+ Misses         93       74      -19     

Impacted Files	Coverage Δ
pystac_client/__init__.py	100.00% <ø> (ø)
pystac_client/cli.py	67.04% <77.77%> (+2.33%)	⬆️
pystac_client/item_search.py	80.90% <86.44%> (+0.15%)	⬆️
pystac_client/stac_io.py	92.00% <91.11%> (+1.09%)	⬆️
pystac_client/client.py	96.36% <92.85%> (-2.21%)	⬇️
pystac_client/conformance.py	96.55% <96.42%> (-3.45%)	⬇️
pystac_client/exceptions.py	100.00% <100.00%> (ø)
pystac_client/version.py	100.00% <100.00%> (ø)

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[duckontheweb]

Haven't had a chance to look through the item_search.py changes in detail, but the rest looks good. I really like this new way of handling the conformance classes and the new mixin!

[duckontheweb]

Sorry this review came in so piecemeal, I didn't have a chunk of time to actually devote to this until just now.

It looks like scripts/build-docs fails because there are still some references to classes that were removed from client.rst. It also looks like there's something weird going on with the published documentation. I get a "SORRY This page does not exist yet." message from the site. There seems to generally be some places where the docs haven't caught up to the code yet. Not sure if you want to fix that in this PR, but it might be worth tracking so that things don't get too out of sync.