[feature] Differentiate between video + image size limits again in configuration

[tsmethurst]

From the Matrix chat:

In previous versions we had media-image-max-size: 10MiB and media-video-max-size: 10MiB in config.yaml file. Now we have the same value regardless multimedia type. This value was useful for clients that automatically downscale big images to follow instance rules (ie. Tusky). Have you considered bringing it back?

I don't think any of us realized this but some clients (Tusky is great) used those sizes as targets to scale down images before uploading. Since this is a pretty cool feature, we could look at splitting up between local video + image size limits again.

[NyaaaWhatsUpDoc]

we definitely should keep the remote vs local distinction though. maybe add more granular image vs video just for local? would definitely be much simpler that way not requiring such fanangling in the media processing pipeline itself

[tsmethurst]

Oh yeah the remote vs local should definitely stay, that's really useful.