Support for ProxyCommand

[tbnguyen1407]

Is your feature request related to a problem? Please describe

Currently ProxyCommand in ~/.ssh/config is ignored when using sake exec or sake run. Only sake ssh seems to support.

Describe the solution you'd like

Support for ProxyCommand

Additional context

ProxyCommand is required e.g. when using SSH over SSM on AWS

~/.ssh/config
Host myhost
  HostName i-abcdef
  User ec2-user
  IdentityFile /path/to/identity
  ProxyCommand sh -c "aws ssm start-session --target %h --document-name AWS-StartSSHSession --parameters 'portNumber=%p'"