Add support for usernames already defined in ssh config

[joshunger]

Is it possible to add support for usernames already defined in the ssh config? It isn't technically "passing" it but ssh just uses it. This is how I believe Ansible works. This would be very helpful so (a) usernames aren't hardcoded and (b) a username configured already for the server in ssh so you don't duplicate the definition elsewhere.

An easy example is ec2-user for Amazon Linux instances. I already have this defined in my ssh config. I'd like to avoid defining it in another spot.

[pstadler]

Please check this.

#117 (comment)

PRs are welcome, as I don't have much time to work on open source projects currently.

[theY4Kman]

As an FYI (and shameless plugging), flightplan-sshconf provides support for reading from SSH config files to fill unpassed connection options.