migrate docs theme to sphinx-immaterial

[rkingsbury]

Move docs theme to sphinx-immaterial since sphinx-material is no longer maintained, as noted by @ugognw in #262 .

Work in progress.

Closes #262

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.87%. Comparing base (e6dde9d) to head (d1bd10b).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #272      +/-   ##
==========================================
- Coverage   81.90%   81.87%   -0.03%     
==========================================
  Files           9        9              
  Lines        1503     1501       -2     
  Branches      261      261              
==========================================
- Hits         1231     1229       -2     
  Misses        226      226              
  Partials       46       46              

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[rkingsbury]

Current warnings / errors

building [html]: targets for 24 source files that are out of date
updating environment: [new config] 24 added, 0 changed, 0 removed
reading sources... [ 25%] amounts .. class_solution
reading sources... [ 50%] contributing .. examples/pyeql_tutorial_activity
reading sources... [ 75%] examples/pyeql_tutorial_carbonate .. internal
reading sources... [100%] license .. units
/home/runner/work/pyEQL/pyEQL/docs/class_solution.md:: WARNING: Parameter name 'file_path' does not match any of the parameters defined in the signature: ['json_path', 'mkdir', 'json_kwargs', 'pickle_kwargs', 'strict']
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.solutes, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.volume, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.temperature, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.pressure, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.pH, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.pE, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.balance_charge, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.solvent, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.engine, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.database, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.default_diffusion_coeff, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/src/pyEQL/solution.py:docstring of pyEQL.solution.Solution:1: WARNING: duplicate object description of pyEQL.Solution.__init__.log_level, other instance in class_solution, use :no-index: for one of them
/home/runner/work/pyEQL/pyEQL/docs/internal.md:: WARNING: Parameter name 'scale' does not match any of the parameters defined in the signature: ['solution', 'solute']
/home/runner/work/pyEQL/pyEQL/src/pyEQL/engines.py:docstring of pyEQL.engines.NativeEOS.get_osmotic_coefficient:: WARNING: Parameter name 'scale' does not match any of the parameters defined in the signature: ['solution']
/home/runner/work/pyEQL/pyEQL/src/pyEQL/activity_correction.py:docstring of pyEQL.activity_correction._pitzer_log_gamma:: WARNING: Parameter name 'temperature' does not match any of the parameters defined in the signature: ['ionic_strength', 'molality', 'B_MX', 'B_phi', 'C_phi', 'z_cation', 'z_anion', 'nu_cation', 'nu_anion', "temperature='25 degC'", 'b=<Quantity(1.2', "'kilogram ** 0.5 / mole ** 0.5')>"]
/home/runner/work/pyEQL/pyEQL/src/pyEQL/activity_correction.py:docstring of pyEQL.activity_correction._pitzer_log_gamma:: WARNING: Parameter name 'b' does not match any of the parameters defined in the signature: ['ionic_strength', 'molality', 'B_MX', 'B_phi', 'C_phi', 'z_cation', 'z_anion', 'nu_cation', 'nu_anion', "temperature='25 degC'", 'b=<Quantity(1.2', "'kilogram ** 0.5 / mole ** 0.5')>"]
/home/runner/work/pyEQL/pyEQL/src/pyEQL/equilibrium.py:docstring of pyEQL.equilibrium.adjust_temp_arrhenius:: WARNING: Parameter name 'reference_temperature' does not match any of the parameters defined in the signature: ['rate_constant', 'activation_energy', 'temperature', 'reference_temperature=<Quantity(25', "'degree_Celsius')>"]
/home/runner/work/pyEQL/pyEQL/docs/internal.md:: WARNING: Parameter name 'temp_ref' does not match any of the parameters defined in the signature: ['c1', 'c2', 'c3', 'c4', 'c5', 'temp', 'temp_ref=<Quantity(298.15', "'kelvin')>"]
/home/runner/work/pyEQL/pyEQL/src/pyEQL/equilibrium.py:docstring of pyEQL.equilibrium.adjust_temp_vanthoff:: WARNING: Parameter name 'reference_temperature' does not match any of the parameters defined in the signature: ['equilibrium_constant', 'enthalpy', 'temperature', 'reference_temperature=<Quantity(25', "'degree_Celsius')>"]