[Update] Approve "Animated Studios"

[AdultSun]

Needs official approval: https://guidelines.stashdb.org/docs/studios/adding-studios/#animated-studios

It was decided early on to limit animated scenes to only "professional studios" and not "independent creators." This keeps it in line with how we handle other scene-types that are predominantly fan-made like compilations and PMVs. The description explains that this was a decision intended to "move slowly" with this content, expecting that opening ourselves up to content on digital marketplaces, Patreon subscriptions, etc. would be too difficult to manage in the early stages of the StashDB project. We also don't allow more traditional scenes/movies hosted on digital marketplaces and Patreon subscriptions either, so this is still in line with the broader consensus regarding those platforms as well.

Also, this policy is currently only explained here under the "Studios" section. I feel like it needs to also be explained under "Scenes" as well since it addresses what kinds of scenes are currently eligible to add onto StashDB.