Add Alpine tags to go-images

[dagood]

Right now we have Debian, Mariner, and Windows images. Upstream also has Alpine. However, apparently the linux-amd64 distribution of Go doesn't work there and it has to be recompiled in-place:

https://github.com/docker-library/golang/blob/7db3fb743f7d5d24d75493eacfc0595ce97979da/1.17/alpine3.15/Dockerfile#L54

(I believe the reason is that Alpine uses musl where other distros use glibc.)

It would be nice to not have to do fresh builds inside our Docker repository, so it would be nice to not do this, but if we do, we could add musl builds to our internal rolling build to avoid building Go in go-images.

[dagood]

Alpine is not supported by the Go maintainers: golang/go#19938

docker-library/golang#250 (comment):

I think our image description should probably link directly to golang/go#19938 -- to summarize that thread's current state, Alpine is not actually an officially supported target for the maintainers of Go (it's non-trivial enough to get the test suite passing on Alpine that we're coming up on two years since it was first attempted in earnest).

The reason this is relevant here is that if we add more Alpine-related variants, I'm afraid it will lend more to the appearance of Alpine being something not only supported, but potentially even recommended by the Go team, which is definitely not accurate (and if we had a clean way to de-emphasize our current Alpine variants until that issue is resolved and upstream officially supports it, I would definitely be considering it).

I think we should not add Alpine, but if we do, we should include "alpha" or a similar marker in the tag name. We have the opportunity to deemphasize these tags because we'd be producing tags that nobody has used before from MCR.