Add a "needs" option to projects, actions and groups

[LauJosefsen]

Should work like gitlab CI, creating acyclic graphs of execution.

[LauJosefsen]

If a needs: string[] is specified, a priority cannot be specified

Order of execution:

• (Verify graph is acyclic)
• Select all actions without a needs key
• Group those actions by priority
• For loop those priority groups:
  • When an action is resolved, go through the remaining action and pop the resolved action from all needs.
  • If a action now has an empty needs array, add it to execution
  • IF list of actions executing is empty, go to next priority group
• IF the list of actions to be executed is NOT empty, report error. This should not happen, if the graph is verified acyclic to begin with.