New PR closes #284 regarding adding scalar boundary conditions

[Jiya-Rathi]

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Example
• Documentation

Description

Is your feature request related to a problem? Please describe.
Closing the implementation gap of MOLE functionality between MATLAB/Octave and C++

Describe the solution you'd like
Building on @jbrzensk proposed AddScalar function C++ implementations (for multiple dimensions), we will complete the implementation using C++ functional overloading + reducing the duplication of code by creating addition functions used in the set up of non-periodic boundary conditions. In addition, extra tests have been added.

Describe alternatives you've considered
We explored the @jbrzensk original implementation and reduced code redundancy and use C++ function overloading. We are testing @jbrzensk original tests + additional functional tests. Remove some special characters from the comments that were causing issues

Additional context
For compatibility with existing tests, we will provide 3 header functions that call AddScalarBC (overloading) for the 1D, 2D, 3D cases. The tests call these header functions (i.e., AddScalarBC1D, AddScalarBC2D and AddScalarBC3D)

Related Issues & Documents

• [] I have created an Issue that is paired with this PR
• Closes Non-periodic Scalar Boundary Conditions #284

QA Instructions, Screenshots, Recordings

Build using the instructions in the README.md and then run the executable called test_addscalarbc

Added/updated tests?

• Yes
• No, and this is why: please replace this line with details on why tests
  have not been included
• I need help with writing tests

Read Contributing Guide and Code of Conduct

• 📖 I have read the MOLE Contributing Guide: https://github.com/csrc-sdsu/mole/blob/main/CONTRIBUTING.md
• 📖 I have read the MOLE Code of Conduct: https://github.com/csrc-sdsu/mole/blob/main/CODE_OF_CONDUCT.md

[Tony-Drummond]

I have reviewed this work. It can be merged to main as it is but Jiya and I would like to suggest to clean the implementation further and replace the calls to addScalarBC1D, addScalarBC2D and addScalarBC3D from the examples and tests with calls to addScalarBC (C++ overloading) directly.
The current implementation of addScalarBC is called inside the functions addScalarBC1D, addScalarBC2D, and addScalarBC3D. Removing these functions, will require updating the tests and examples files.
What do others think?