[WIP] Introduce a skill id enum to make handling more centralized an robust

[jon-zu]

This introduces a new package meta and a SkillId enum to attempt to remove most hard coded parts. Just a proof of concept for now.

Some issues may arise:

1. Temporary Stats reason is rather a multi value, like Items buffs would be invalid Skill Ids
2. Performance concerns due to conversion via SkillId.fromValue
3. Some hidden skills are not yet part of the enum