Jsonized all Mutations and Mutation categories. [Ready]

Removed the pl_flags enum and replaced it with a map.
New Character Traits window rewrite.
Added: Character creation > trait selection menu improvements [https://github.com/CleverRaven/Cataclysm-DDA/pull/2496 joshuagiles]
Mutation Wish menu rewrite.
Recalc mutation_category_level on load and after mutation changes.