Develop 5e character sheet check

[megw-school]

Helper functions that check character sheet fields are compliant with 5e rules.

[kevy-kev]

Once again I tried to assign multiple people to an issue and it wouldn't let me.. in my defense on the projects board view it said "assign up to 10"

[megw-school]

Implemented a point buy validation helper and a selection validation helper along with tests. Point buy validation is for checking and correcting ability scores. Selection validation is for checking and correcting anything that provides options. For example, across race, class, and background there are required values for things like skill proficiency, tool proficiency, and languages, but sometimes there are also opportunities for choosing from a subset. Selection validation will check that required values were provided along with valid selections from various choices.

Point Buy Validation

• Checks if scores are valid. Invalid scores use too many points, have invalid score values (i.e. above 15) , or didn't use enough points
• Greedily corrects scores by prioritizing the highest value scores and removing/adding points accordingly

Selection Validation

• Checks selections against a provided ruleset. Rulesets are generated by Class, Race, and Background objects. Checks selections match required and choice sets.
• Greedily corrects selections to ensure they match the ruleset. It will try to keep the original selection as much as possible.