Support for animated image stitching

[cparinn]

Is your feature request related to a problem? Please describe.

When I try to stitch together two animated images (such as GIF) they become still images.
I would like to be able to create something like this or this (without needing the spacing, frames or collage components necessarily)

Describe the solution you'd like

Implementing #881 or #888 might be able to solve this in addition to their suggestions. I'm not sure if another library is required to make this work. It's ok if the GIFs or animated images need to have the same number of frames, I can edit them to do so.

Describe alternatives you've considered

Websites and other apps mostly, but it has been difficult to find alternatives, let alone ones that are FOSS. Others besides myself have wondered why there are no apps that seem to support these functions. Link to similar 2 year old thread

[T8RIN]

interesting

[T8RIN]

I've looked the only way is to extract frames from each gif and combine each layout then back to gif, this seems to be really long and crashy operation