Provide option to disable autostart of apps on restart of stack

[ZeHiro]

Currently, on typing cozy-monitor restart-cozy-stack, applications which were launched before the command are automatically restarted after the data-system (and before the home and proxy). Problem : data-system can use a lot of resources on restart, and on raspberry pi, the combination of data-system awaking and all the apps launching can cause the data-system to be kicked by the oom system.

cozy-monitor restart-cozy-stack --no-app could only restart the stack apps but not all the other apps.