[creature] Define dominance pattern for traits in multi-racial creatures

[joelalejandro]

Suppose we have a creature that is half-human, half-cat.

We want to create it using multiple races, as described in #28. So we define Human and Feline as races:

const HumanRace = new Race({ 
  age: 90, 
  alignment: CreatureAlignment.Neutral, 
  size: CreatureSize.Medium 
});
const CatRace = new Race({ 
  age: 15, 
  alignment: CreatureAlignment.NeutralEvil, 
  size: CreatureSize.Small 
});

Such hybrid creature could be expressed as:

const FelineHumanoid = new Creature({
  races: [HumanRace, CatRace],
  name: "Feline Humanoid"
});

How would the traits be defined for this instance?

• A possible way would randomize between the ranges of possibilities defined by each race. So, for the age, any feline humanoid creature would have a maximum age between 15 and 90, they could be either Small or Medium in size and be aligned as Neutral or NeutralEvil.

• We could cascade the values from race A to race B (which would make the races list order-sensitive).

• We could drop "multi-racial" support in terms of defining hybrid races as specific races, such as:

  const FelineHumanoid = new Race({ /* ... */ });