[Feature Request]: Dynamic OG image generation in AstroPaper blog posts

[mtrucc]

Is your feature request related to a problem? Please describe.
When the number of articles is too large, it will take a long time to generate the OG image.

Describe the solution you'd like
I have more than 500 articles. An og image will take 1 second, so I have to wait 10 minutes for the generation to be completed.

Describe alternatives you've considered
I think an option should be added to add a default og image globally