Do not clear/replace console on `stack ssh` command

When SSH'ing into a stack, the current console backscroll is replaced wholesale. This makes it frustrating to work in a session on and off, as your prior commands are constantly removed from view when you reconnect, and you need to copy any output to a safe place before starting fresh.

VIP's CLI starts inline without replacing what came before, and I find that an overwhelmingly more usable experience.

I'd like to suggest we alter the `ssh` subcommand to not clear the terminal on connection, if possible.