Jump Host SSH configuration support

What is SSH Jump Hosting ?
- A jump host (also known as a jump server) is an intermediary host or an SSH gateway to a remote network, through which a connection can be made to another host in a different security zone, for example, a demilitarized zone (DMZ). It bridges two dissimilar security zones and offers controlled access between them.
- Source : tecmint
Why ? Use case ?

Each time a user wants to manage / provision a private server that should not be accessable from internet directly. Ensure stronger security.
Saving unused IP Addresses : What is the logic to have a public IP for a DB server that will not be accessible publicly but only on his private interface. We have a public IP and a FW that block every incomming connections for security.
In case of a VM server that manage some VM that should not be publicly visible enable the possibility to use ploi as a server manager anyway even if the server have only a private IP.

FEATURE REQUEST
- Add the possibility to specify "JUMP HOST" configuration on custom servers (with a Tab maybe). On this TAB adds the following additional fields :
  - Add a field Jump host user
  - Add a field Jump host IP
  - Add a field Destination IP
  - Add additional documentation : User needs to add ploi ssh key to the jump host server to allow connection on the jump host (should be with very limited access as it just is used as a relay to the final host).
- connect to the server using the provided data, ie : ssh -A -J user@jump-server user@destination server