Added listonboardingproviders command-line interface to list available providers for client on-boarding

usage:
listonboardingproviders
-A,--adminuser <arg> Admin username
-h,--help Prints a help text
-p,--port <arg> The optional RMI port (default:1099)
-P,--adminpass <arg> Admin password
--responsetimeout <arg> The optional response timeout in seconds
when reading data from server (default: 0s;
infinite)
-s,--server <arg> The optional RMI server (default: localhost)