Create sd-webui-predefined_aspect_ratios.json

[zentrocdot]

Info

First time, that I wrote an Extension for AUTOMATIC1111. By use of 'Install from URL' installations works fine. First version of documentation is finished. So I can try to do this pull request.

Checklist:

• I have read the Readme.md
• The description is written in English.
• The index.json and extension_template.json have not been modified.
• The entry is placed in the extensions directory with the .json file extension.

[zentrocdot]

I've never had to do anything like a pull request before, so I'm curious to see how it works now.

[w-e-w]

sorry I'm bit busy recently
I will take a look at this when I can
just leave it open

[w-e-w]

redirect

• Pull request for sd-webui-aspect_ratios-dd #375