fix: make interface of `NCRModuloP` fail-safe

[vil02]

Description of Change

The original implementation of NCRModuloP, has two problems:

• the member variable fac is one element too short,
• the computation math::ncr_modulo_p::NCRModuloP(100, 43).ncr(10, 3, 13) returns 2, which is incorrect since10C3 = 120 and 120%13 = 3 (note different values of p).

This PR fixes above issues and does some minor refactoring, style improvements and adds missing test cases.

Checklist

• [x] Added description of change
• [x] Added tests and example, test must pass
• [x] Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• [x] Relevant documentation/comments is changed or added
• [x] PR title follows semantic commit guidelines
• [x] Search previous suggestions before making a new one, as yours may be a duplicate.
• [x] I acknowledge that all my contributions will be made under the project's license.

Notes: Updates to fail-safe API of NCRModuloP

[realstealthninja]

Please do not resolve unless you have instructions to do so or the changes are sufficiently discussed

[vil02]

@Panquesito7 could you please have a final look?

[vil02]

@Panquesito7, @realstealthninja could you please have a final look?

[github-actions[bot]]

This pull request has been automatically marked as abandoned because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[vil02]

@Panquesito7, @realstealthninja please dont-close.