Document OpenVPN local and remote network list options

The local and remote network fields can now have lists of CIDRs, so modify the GUI so it describes this.
Note: I also change the client advanced example. The route command is not longer needed, so I gave an example of the remote command, which is useful.
I didn't do the same in the server advanced example, since remote is not relevant, and I couldn't quickly think of a good example to put there.