List existing resellers

When run with no parameters, this program simply displays a reader-friendly table of existing Virtualmin resellers. The only supported options are --multiline, which causes it to show more details about each reseller in a format suitable for reading by other programs, and --name-only to dump just a list of reseller usernames.

usage: list-resellers.pl   [--multiline | --name-only]
                           [--name username]