Populate extension images

[holly-cummins]

We can do this in several ways, and should do some of them:

• GitHub repository image (https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/customizing-your-repositorys-social-media-preview). This is almost great, but the images are intended to be rectangular, and with text, such as this one
• Repository owner's image, usually an org logo
• New, manually populated, field in the extension yaml (but where should the image live? it needs to be a stable URL. git is a possibility, but is there something better?)

Extensions in the quarkus repo will need a manual override to avoid a sea of Quarkus logos appearing on the main page. However, we don't want to force people to manually enter information that's already available elsewhere.

I think we may be able to mostly do the right thing for the GitHub repository image. If you look at something like this, it's not suitable:

But something like this should be used.

The difference is one is set by the user, and one is the github default. I don't think the github api distinguishes between the two, but we can use some heuristics. In particular, we'd only want to show images with no text. This is something we can detect.

We also would want to crop. https://www.npmjs.com/package/smartcrop can probably help with this.

• Use GitHub org's avatar as a default
• Get avatar from GitHub API, rather than guessing it
• Use social media preview, if it has no text and crops well
• Honour overrides in extension yaml
• Document how to set an image (https://quarkus.io/guides/extension-metadata#quarkus-extension-yaml, anywhere else?)

[holly-cummins]

And it's live, with the github option: