rainbow-run: Create and use rainbow-isolated instances

OPTIONS

--version: show program's version number and exit
-h, --help: show this help message and exit
-v, --verbose: Verbosity. Repeat for more verbose output.
-q, --quiet: Quiet. Disable all output.
-s SPOOL, --spool=SPOOL: Location of the rainbow spool.
-e ENVDIR, --envdir=ENVDIR: Location of an envdir describing the desired environment.
-E ENV, --env=ENV: Environment bindings to override.
-c CWD, --cwd=CWD: Working directory.
-f FD, --fd=FD: File descriptor number to leave open.
-i ID, --id=ID: ID of shared-data group.
-o OPTION, --option=OPTION: Options: video, audio, serial, constant-uid, x11, network.
-p PERMISSIONS, --permissions=PERMISSIONS: Location of a permissions.info file.
-u USER, --user=USER: Owning user.
-r RESUME_USER, --resume-user=RESUME_USER: Resume <user>.
-a ASSISTANT, --assistant=ASSISTANT: Task-specific assistant.
-G GROUP, --group=GROUP: Extra groups.