[feat] Use GH Actions to compile a repo summary that can be downloaded directly through GH pages

[chrisguida]

from @cdecker: Any chance we can use GH Actions to compile a repo summary that can be downloaded directly through GH pages (saves the SSH connection overhead, and does not need a full (recursive) clone)? That'd be perfect to keep the repo metadata sync minimal and quick. (see the sparse crates.io metadata refresh deployed in 1.71 as an example of what the advantages could be).

cc @endothermicdev

[chrisguida]

I imagine this would be fairly easy to implement with the badges branch @sip-21 added to deploy the CI badges.

What format do we want the metadata to be in?

cc @endothermicdev Guessing this is for reckless?