Establish local and remote paths plus get settings file contents
If we're choosing a path pair, get the number and the 2 chosen paths
(local and remote). Paths are not valid until checked if exist. Prior to
that, a mkdir is attempted if it doesn't with error reporting if that
doesn't happen.
If valid, set the new root path and reload the file manager
Adding and editing of local and remote array paths on postback also
handled
Page displays form & table so you can manage repo pairs along with
providing usage info
