We only append the chan_id and the human readable scid
for the commands `listchannels` and `closedchannels`. This
ensures that other commands like `buildroute` are not affected
by this change so their output can be piped into other cmds.
For some cmds it is not very practical to replace the json output
because we might pipe it into other commands. For example when
creating the route we want to pipe the result of buildroute into
sendtoRoute.
We want to export some of our CLI code to re-use in other projects. But
in Golang you cannot import code from a `main` package.
So we need to move the actual code into its own package and only have
the `func main()` in the `main` package.
