Modpacking wizard, merging spells and ability_master into ability extension.

[MistakeNot4892]

Extremely WIP.

• [X] Deletes ability_handler and associated screen element.
• [X] Adds generalized handling for ability and screen elements to /datum/extension/abilities.
• [X] Adds generalized hooks to ability extension where appropriate for ability updates.
• [X] Moves wizard mode, antag and various props/spells/outfits into a modpack.
• [ ] Converts /spell type to a subtype of a generalized ability decl/metadatum system.
• [ ] Reimplement cult spells.
• [ ] Update deity spell code.
• [ ] Update scroll, contract and spellbook type to behave correctly with their inherited behavior.
• [ ] Makes sure all this stuff actually works.