Support for system ancestry

[QMalcolm]

Most TTRPG rule systems include ancestries that come with specific traits/features/stat modifies. We should support this. There will likely be a long tail of edge cases for various rule systems.

Note: We'll be using ancestry, but in many systems it's referred to as race. We're using ancestry because it is a more apt description of what is typically conveyed by race. Additionally we have planned support for component aliases in #22 which will allow one to alter naming to match how it is referenced by the rule system.