Reboot via ssh when DELL server is detected

I had to move the shell function to the Server class, to be able to use it from itself.

This code is working fine with DELL servers, I've tested it a couple of times.

Also, I've added a 'debug' dot while you are waiting for the server to reboot, you can throw it away, or maybe leave only when some flag is used. It's useful when you are working remotely and don't know if you're waiting or your ssh session is dead.

NOTE1: We can do some tests now because we're setting up new servers and they are not online yet.
NOTE2: I was not able to test if everything is still working on the non-dell servers cause all ours are in production now.