slapos node boot: Start computer partitiong without connecting to master
When computer reboot, the node should be able to restart services without need to connect to master.
slapos node boot command will invoque slapos node format with --local parameter (to setup computer partition IPs) so that xml is not posted to master.
All partition that was previously started will be immediately started by supervisord.
bang is still called. If there is network issue, slapos node instance will run when the node will be able to connect to master (for now).