Move CLI stuff into its own dir

I think having it in its own dir like this means that people can include it in their own projects as they wish. Even though the CLI does nothing currently.
I'm not sure what happened to my previous comment. I think I hit send after you rebased so it got lost in the ether, but:

I believe that when `go install`ed the binaries will be named after the file that has the `main()` func. As such, I think this should be fully qualified as `lifx-snoop` so that it makes sense when added to their `PATH`. I could be wrong about this behavior so it should be experimented with but I definitely don't want to add a vague `snoop` tool.