Feature: telnet, ftp provisioner

Add a telnet provisioner, using FTP to transfer scripts, on behalf of legacy guest operating systems that do not have ssh, scp servers available.

Telnet provisioning with the option to inline scripts, is likely required for single-user operating systems that cannot run a file server application and a remote shell application concurrently.

Finally, (hot)key delays, for inline scripts and general telnet commands; and delays between telnet client session connections, will be required to ensure reliable communication for some graying telnet servers such as rmenu.