use ko to build svc container images

[SoMuchForSubtlety]

Changes the CD action to use ko^1, so we don't need qemu and can use the go build cache.

TODO:

• [x] use a custom base image
• [x] test the action
• [x] remove the svc-ci action?
• [x] remove the old dockerfile?
• [x] link ghcr.io/memelabs/strims/ffmpeg to this repo
• [x] fix ffmpeg apko action or switch to qemu + buildx

[jbpratt]

@SoMuchForSubtlety you'll need to disable the PR event trigger, I don't think it's allowed to push (and shouldn't be)

[jbpratt]

~4m build @slugalisk :partying_face:

[SoMuchForSubtlety]

~4m build @slugalisk 🥳

~1m 😏

[slugalisk]

~4m build @slugalisk 🥳

~1m 😏

🤯