retry

Added

• Command-line parameter --retries to alter maximum number of attempts to send a command
  to a SwitchBot device (default unchanged)

Fixed

• Dockerfile: split pipenv install into two stages to speed up image builds
• Dockerfile: chmod files copied from host to no longer require o=rX perms on host
• Dockerfile: add registry to base image specifier for podman build
• Dockerfile: add --force flag to rm invocation to avoid interactive questions while running podman build