[quick bar]support \p cmd

when login remote telnet, create a cmd bar to auto login,
after input username must wait for a moment to remote display the respone,
then we can input the password.

the secure crt implement \p to sleep one second to wait the respone, the securt crt cmd is:
my_username\n \p my_password\n #---the \p is sleep one second

No files or tests are named. Start by locating the quick-bar command parser and the Telnet login flow, then trace how username and password input are sent. Done means the \p command pauses long enough after the username before the password is submitted, with coverage for the command-bar behavior.

Written by the indexing model from the issue text.