Add aspect ratio dimensions for Twitter

[skllcrn]

It'd be great to have presets optimized for Twitter and other common ones:

[romfrancois]

Hi there, I'd like to contribute on this project and this piece of work.
However would it possible to get more info, specs, etc as to what to expect, visually and functionally please?

I've quickly prototyped something (attached) and would like to know if that's the right direction.

Many thanks,
Cheers

[sammig6i]

Hi, I'd love to contribute to this issue. I think I could also add aspect ratios for the different social media video standards as well.

Thanks!