Add a sponsor button to profiles having Sponsorships enabled

[Gummibeer]

We should add a "sponsor" button on all profiles having sponsorships (via GitHub) enabled.
To do so we will have to sync if they have sponsoring enabled in the \App\Jobs\UpdateUserDetails job which will also have to switch to GraphQL API as the sponsor information isn't available elsewhere.

This should also result in a PR to https://github.com/Astrotomic/laravel-github-sponsors with a method like hasSponsorsListing() or hasSponsoringEnabled().
https://docs.github.com/en/graphql/reference/objects

With the new attribute on user and organization we can show a conditional button on all profiles linking to the GitHub sponsor page.