User initialization of EP TTP ionic model states

[kko27]

Current situation

Resolves #407

Release Notes

• Can initialize ionic state variables of TTP EP model from solver.xml file
• Outputs warning message to user that default EP initial conditions have been selected

Testing

New test case in tests/cases/cep/spiral_TTP_2d that applies 4 different sets of initial conditions to the simulation domain.

Code of Conduct & Contributing Guidelines

• I agree to follow the Code of Conduct and Contributing Guidelines.

[codecov]

Codecov Report

❌ Patch coverage is 80.67633% with 40 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.93%. Comparing base (fbf70b4) to head (74e35a7).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
Code/Source/solver/Parameters.cpp	70.65%	27 Missing ⚠️
Code/Source/solver/CepModTtp.cpp	87.32%	9 Missing ⚠️
Code/Source/solver/read_files.cpp	91.42%	3 Missing ⚠️
Code/Source/solver/VtkData.cpp	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #522      +/-   ##
==========================================
+ Coverage   67.79%   67.93%   +0.14%     
==========================================
  Files         168      168              
  Lines       32798    32898     +100     
  Branches     5767     5783      +16     
==========================================
+ Hits        22234    22350     +116     
+ Misses      10426    10410      -16     
  Partials      138      138              

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[kko27]

@ktbolt and @javijv4 I think this is ready for review. Several changes have been made, as discussed in #407

[kko27]

I'm almost done with this PR. Currently checking/debugging why the solver doesn't throw an error if a required parameter is missing