Run is the top-level entry point to the CLI plugin framework.

RunningStandalone tells a CLI plugin it is run standalone by direct execution.

RunPlugin executes the specified plugin command.

CLIPluginSocketEnvKey is used to pass the plugin being executed the abstract socket name it should listen on to know when the CLI has exited.

PersistentPreRunE must be called by any plugin command (or subcommand) which uses the cobra `PersistentPreRun*` hook.