netkit-telnet: add new recipe

netkit-telnet includes the telnetd and client.
telnetd: daemon for telnet protocol.
telnet: client for telnet protocol.

Signed-off-by: Li Xin <lixin.fnst@cn.fujitsu.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>