Modpacking wizard, merging spells and ability_master into ability extension.

[MistakeNot4892]

Extremely WIP.

• Deletes ability_handler and associated screen element.
• Adds generalized handling for ability and screen elements to /datum/extension/abilities.
• Adds generalized hooks to ability extension where appropriate for ability updates.
• 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.

[MistakeNot4892]

This has turned into something like four PRs mashed into one.

• Stamps rewrite/generalization.
• Scroll repath onto /paper and paper generalization.
• Staffs, canes and brooms rewrite, stance support generalization.
• Broom sweeping mechanics.
• Ability system expansion and rewrite.
• Wizard spell conversion to abilities and modpacking.

Someday I may finish it.