docker refinements

[gotjoshua]

docker-compose

• [x] separate services for p2p, store, and gateway ( ae360e98f99b4e79a898161cb0aae30855ad6928 )
• [ ] volume mounts for persistence

Dockerfile

• [x] add ~/.iroh/bin to PATH ( ae360e98f99b4e79a898161cb0aae30855ad6928 )
• [ ] non-root user

[gotjoshua]

do either the gateway or p2p services need any volumes ?