Add a new Docker image variant (tag: self) that uses compiled binaries
from the hapi self branch instead of installing from npm.
- self/Dockerfile: runtime image copying pre-built binary by arch
- self/build.sh: local build script from ../hapi/dist-exe
- .github/workflows/docker-build-self.yml: CI workflow to build and
push multi-arch image to GHCR with tag "self"
via [HAPI](https://hapi.run)
Co-Authored-By: HAPI <[email protected]>
