Allow installers to stop processes when a condition is reached

[mirkobrombin]

Problem

Some installers launch the program when the installation end, blocking the Bottles installation process (https://github.com/bottlesdevs/programs/pull/62) other steps are performed only when the main process exit.

Solution

Implement a new exit_on parameter for the run_exe/run_msi action, which starts a monitor that stops a list of processes when a specific process comes up.