Refactor to allow extension of module uris

[hinshun]

• Bring consistency of info.Stdin, info.Stderr to other commands
• Bring consistency of module parsing to other commands
• Allow extension of module URIs
• Refactor remoteDirectory to solver.NewRemoteDirectory

Stdin handling

❯ hlb run -
fs default() {
    image "alpine"
}
#1 resolve image config for docker.io/library/alpine:latest
#1 DONE 0.4s

#2 docker-image://docker.io/library/alpine:latest
#2 CACHED

Use Ctrl+D to terminate stdin input.

❯ echo 'fs default() { image "alpine" }' | hlb run -
#1 resolve image config for docker.io/library/alpine:latest
#1 DONE 0.4s

#2 docker-image://docker.io/library/alpine:latest
#2 CACHED