Implement dependency management

[stdevel]

Is your feature request related to a problem? Please describe.
It would be great to have dependency management for automated patching. Think about two systems:
app running a application server that uses a database running on db.
When db requires a reboot, app needs to be stopped before that.

Describe the solution you'd like
It would be great to have dependency management (e.g. a simple depends_on per system) that can be stacked (e.g. web depending on app depending on db).

Describe alternatives you've considered

Additional context