Docker Swarm Mode has been in severely declining usage and maintenance for years now. Meanwhile, Docker Compose has had quite a lot of changes (notably deprecating the `version:` field required by Swarm / forward compatibility). As a result, it no longer makes a ton of sense for us to prefer/suggest Swarm usages.
This changes all references to be `compose.yaml` (the upstream-preferred canonical filename: 9a9cc5d9c3/cli/options.go (L384-L385)) directly, leaving "swarm compatibility" as an exercise for the minority of readers who might still need/want it.
Unfortunately, this also means we need to remove all the play-with-docker links (since it only supports stack deploy via URL arguments, not compose), but my experience with that service is that it hasn't been terribly performant for a while, so I don't think this is a huge loss.
(There were also a few trailing references to the long-since-defunct Docker Machine project which have also been cleaned up.)
This was the result of some great feedback from David Messina that it's not obvious when a user lands on a page like https://hub.docker.com/r/arm32v7/docker that it's actually an official part of the official images program, and there isn't an obvious/consistent link *back* to the primary manifest-listed library image, which users should typically prefer to use if their platform/environment supports doing so.
This uses the combination of us pushing to a namespace + `BASHBREW_ARCH` being set to determine whether we're pushing to an arch-specific page and should thus appropriately filter all content to the current architecture.
This should make it much faster to find the right place to file issues, get help, find out whether upstream maintains an image, etc.
I've done my best to represent each `REPO/maintainer.md` file appropriately, but I might have missed some (or there might be something else a maintainer prefers be listed there, either more or less descriptive, for example), which would be welcome contributions following this change.
- First pass on source docs for backdrop
- Update update.sh to include backdrop
- Added user feedback links.
- Expanded the 'what is Backdrop' section.
- Fix up some MD linting chaos for backdrop