Wait for an <exec> action to complete before executing the next action

[Antoine Beauchamp]

Is your feature request related to a problem? Please describe.
Using the <exec> action start a process but does not wait for the process to complete/exit gracefully.
If this process requires a few seconds before completing, the next action is started before the first process has time to complete.

Most use cases uses the <exec> action as the last action. The behavior explained above is usually not a problem. However, if one needs to use multiple <exec> actions or have an action that is based on the result of the first action, this actually result in a problem.

Describe the solution you'd like
We should add a wait attribute that when set to true, would tell the system to wait for the process to exit before starting another action. A timeout attribute should also be added that would stop the wait to return the control to File Explorer in case a process never ends (or loop infinitely). If a timeout value is not specified, the timeout time should be set to infinite by default.

Describe alternatives you've considered
N/A

Additional context
N/A