Add Docker.alpine alternative image

[jjcarstens]

For #1427

This builds and starts locally, though I am not Docker-smart enough to actually load a webpage from it.

I believe we could build this alongside with the ubuntu image for a while, maybe with an -alpine tag. But I haven't figured out how to add that to the workflow yet.

/cc @rraub

[joshk]

Very cool.

Looking into the Docker build and push action, you should be able to add this after the current one in ci.yml:

     - name: Extract metadata (tags, labels) for Docker (Alpine image)
        id: alpine-meta
        uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
        with:
          images: ghcr.io/nerves-hub/nerves-hub-alpine
          tags: |
            # short sha
            type=sha,enable={{is_default_branch}},prefix=,suffix=,format=short
            # branch image names, except for main
            type=ref,enable=${{ github.ref != format('refs/heads/{0}', 'main') }},event=branch
            # latest tag for main branch
            type=raw,enable={{is_default_branch}},value=latest
            # tag event (eg. "v1.2.3")
            type=ref,event=tag

     - name: Build and push Docker image (Alpine)
        uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
        with:
          context: .
          file: Docker.alpine
          push: ${{ github.ref == 'refs/heads/main' || github.ref_type == 'tag' }}
          tags: ${{ steps.alpine-meta.outputs.tags }}
          labels: ${{ steps.alpine-meta.outputs.labels }}

[oestrich]

This seems like it would work. Publishing both would be pretty cool

[oestrich]

I think this is for something related to iex maybe... but I'm not sure. Seems fine to skip for now

[oestrich]

Suggested change

	# Is this cleanup still needed?
	# && apt-get clean && rm -f /var/lib/apt/lists/*_*

Nope, drop it!

[oestrich]

Suggested change

	# Do we need to clean things?
	# && apt-get clean && rm -rf /var/lib/apt/lists/*

Nope, drop it!

[joshk]

@jjcarstens did you want to finish this PR?