feat: use only long options to avoid stomping on ssh options

[mariadb-JeffBachtel]

Currently, mssh uses the short option -t which conflicts with an existing ssh option (ptty allocation).

It would be great if the short option(s) could be removed, or if alternatively an environment variable could be set to eliminate short options altogether.

[dko-slapdash]

I found a hacky work-around for this: add a space before "-t" and quote it:

mssh ... -t i-0adf520869ae1a4ca my-host.com " -t" bash

This works, because mssh calls .strip() for unknown arguments:

aws-ec2-instance-connect-cli/ec2instanceconnectcli/input_parser.py

Line 87 in 470ed67

flag = flag.strip()