Enhancement: Variation-specific song scripts

[nebulazorua]

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What is your suggestion, and why should it be implemented?

Song scripts that are used for variations instead of the default song script. Would allow remix mods to use variations to add their remixes to base game songs, without having to override the base game song scripts to add song-specific events (i.e B-Sides Redux Stress having it's own sprites that don't follow the regular tankman running sprite, D-Sides Winter Horrorland has the crowd singing and a different intro to the song)
Could do the song-specific stuff with a check in the stage, but that feels super hacky and on something like Stress you can't disable the existing Stress script without using a diff name for picospeaker and using that for the b-sides pico character.