Create management page so that slave computers can be stopped when they
go wrong.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Bump ssh-slaves and jenkins versions

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
SSH launcher to lookup credentials.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>