alkalinity: add definition based on weak acids and bases

[SuixiongTay]

Summary

Added additional acid and bases including:

• Carbonate species: [HCO3-], [CO3-2]
• Phosphorus species: [HPO4−2], [PO4−3], [H2PO4-]
• Sulfur species: [HS−], [S2−], [HSO4-]
• Others: H3SiO4[-1], B(OH)4[-1]

This PR addresses #299 .

Todos

• numerical efficiency improvements (requires discussion)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.24%. Comparing base (63f4566) to head (27cd1fc).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #398      +/-   ##
==========================================
+ Coverage   86.21%   86.24%   +0.02%     
==========================================
  Files          14       14              
  Lines        1842     1846       +4     
  Branches      319      320       +1     
==========================================
+ Hits         1588     1592       +4     
  Misses        209      209              
  Partials       45       45              

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[SuixiongTay]

Hi @rkingsbury , this branch is ready for review. I realized there is a docs error in the CI and had submitted another PR to address that in #401. Thanks!

[rkingsbury]

Nice contribution @SuixiongTay , thank you! See comments.

In addition to what you have here, please add a test case or two to the existing test_alkalinity_hardness method. These cases should not use equilibrate. Rather, just define some solutions with known compositions (ideally, use one that contains weak acid species other than carbonate) and test the returned value against your manually calculated one.

[SuixiongTay]

Hi @rkingsbury , the PR has been updated and is ready for your review. Thanks!

[rkingsbury]

Looks good @SuixiongTay . Ready to merge after a few small text edits.