Fixed foods and cash foods being applied simultaneously

[csnv]

Pull Request Prelude

• I have followed proper Hercules code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

Fixes stat foods and stat cash foods being applied simultaneously and stacked one in top of the other. Also, only cash foods can overwrite normal foods (and not the other way around) according to @Kenpachi2k13 in this old PR #2741

In addition, being the lesser evil, in this PR cash foods will overwrite the same type of food if the level is also the same. However, according to this comment in the aforementioned PR, cash foods should only overwrite stat foods if the effect is stronger, not equal. Please, let me know if I should respect the quoted behavior and not let foods be overwriten by foods of equal level.

Also the the old effect will only be canceled if the new one is stronger. Using +1 STR cash food won't cancel +1 STR normal food.

Issues addressed:
#2489