Integrate screenshots in documentation

[PoignardAzur]

#832 add a way to add screenshots to documentation

What we need after that PR is merged is to:

• Check whether the docs.rs trick actually works.
• Document the tagging pattern needed to make it work.
• Find a way to add screenshots that will still work with cargo rdme.

[PoignardAzur]

We've had a discussion somewhere (can't find where), where Daniel pointed out that the current setup might burn through our LFS quotas because people will download the image every time they consult our doc.

@DJMcNab is this still a problem?

[DJMcNab]

We discussed it in office hours two weeks ago (https://docs.google.com/document/d/1cL4CywyDJ-AdTyQTYTySYJWCsaq0nT50uV9rliFM6zU/edit?tab=t.0#heading=h.evjimzdnrevx).

It might still be an issue - the docs from GitHub are a bit unclear. The decision we made was to launch it as currently planned, then:

• If it becomes an issue, and chews through our LFS bandwidth, we pay for a single pack of LFS backwidth/data ($5), which should give us enough breathing room, as it provides 50x the current bandwidth
• Release a 0.3.1 which moves the screenshots to a GitHub pages/repository which doesn't use LFS (not necessarily the long-term solution, just to stop the "bleeding")
• (Maybe) ask the docs.rs team to remove the docs for 0.3.0, if it's still getting enough back-traffic

Certainly if someone has the will to move to a properly hosted solution on linebender.org (the exact technical details there are TBD, because we want to keep the screenshots for all previous tags available), then that would be welcome.

[PoignardAzur]

Could we publish the screenshots in a Github release and link to those? I don't think Github release downloads are metered?