ssh behaviour on zos init

[despiegk]

• check ssh-agent is loaded & has 1 key, if yes use that one
• check there is ~/.ssh/... if yes use that one
• if no key, ask user if we should generate one for them, if yes do the generation

[xmonader]

ssh behavior is container only now

[Dina-Abd-Elrahman]

ZOS Version:

1e3f6560ebb9f6b566f603cf76b251c10a67e959

Verification steps:

• create one container with ssh-agent is loaded and have only one key.
• I killed ssh-agent and try to create a new container, it loaded using the key stored in ~/.ssh/...
• I killed ssh-agent and remove ssh key file from default paths and try to create new container and i got this message

dispatch creating test-agent-3 on machine https://hub.grid.tf/tf-official-apps/ubuntu-bionic-build.flist false
ERROR couldn't find sshkeys in agent or in default paths [generate one with ssh-keygen]