Replace absl/absltest with docopt/pytest

[skearnes]

• Replace absl with docopt
• Replace absltest with pytest
• Delete ord_schema/visualizations (now part of ord-interface)
• Remove ord_schema/scripts/migrate_schema.py and *old.proto

[codecov[bot]]

Codecov Report

Merging #628 (7411b4b) into main (c736318) will decrease coverage by 11.72%. The diff coverage is 66.05%.

@@             Coverage Diff             @@
##             main     #628       +/-   ##
===========================================
- Coverage   76.23%   64.50%   -11.73%     
===========================================
  Files          19       16        -3     
  Lines        1990     1854      -136     
  Branches      497      497               
===========================================
- Hits         1517     1196      -321     
- Misses        329      556      +227     
+ Partials      144      102       -42     

Impacted Files	Coverage Δ
ord_schema/macros/workups.py	0.00% <0.00%> (ø)
ord_schema/scripts/parse_uspto.py	0.00% <0.00%> (ø)
ord_schema/resolvers.py	71.42% <75.00%> (+0.31%)	:arrow_up:
ord_schema/scripts/check_pb.py	88.23% <80.00%> (+1.27%)	:arrow_up:
ord_schema/scripts/process_dataset.py	78.98% <80.00%> (-2.19%)	:arrow_down:
ord_schema/validations.py	70.51% <83.33%> (+0.11%)	:arrow_up:
ord_schema/scripts/build_dataset.py	90.47% <90.00%> (+11.68%)	:arrow_up:
ord_schema/scripts/enumerate_dataset.py	87.50% <90.90%> (+8.92%)	:arrow_up:
ord_schema/scripts/validate_dataset.py	90.00% <90.90%> (+1.42%)	:arrow_up:
ord_schema/macros/solutions.py	97.36% <100.00%> (+0.07%)	:arrow_up:
... and 5 more