connect to servers by ssh

A user should be able to do a `deploifai server connect [project-name]/[server-name]` that will establish an ssh connection and tunnel whatever ports that are useful.

The command should do these 3 things:
- download the ssh key
- do `chmod 400` on the ssh key, need to be careful about what works on windows
- make ssh connection with port tunneling, need to figure out a random available port on the local machine to avoid port collision

After running the command, the user should see
- spinners for each step, as they happen, at least for the steps that take some time
- which port on the local machine is being used, and for what service