[#6408] Generalize leveled conditions

[krbz999]

Adds a "Condition" ActiveEffect subtype which is responsible for storing levels and other data related to that on the actor.

Generalizes most of the handling surrounding exhaustion. The attributes.exhaustion property remains for backwards compatibility and for the ability to update the Exhaustion condition via an actor update. For other conditions with levels, one can call actor.toggleStatusEffects(statusId, { levels: 1 }).

For example, adding a new condition,

DND5E.conditionTypes.contamination = {
  name: "Contamination",
  img: "modules/drakkenheim-scgd/assets/layout/meteor.svg",
  levels: 6,
  conditions: {
    4: ["weakened"],
    5: ["dazed", "incapacitated"],
  },
};

will add a new status with 6 levels, where "Weakened" (an unrelated example condition) is applied at 4 leves of Contamination or higher, and Dazed and Incapaciated are applied at 5 levels or higher.

The reduction property is also generalized and can be used by any condition, not just leveled ones.