FR: Allows banners to be time limited

[dantefromhell]

A personal use-case of mine is to announce server maintenance using the banner module.

For this it would be helpful if the display of the banner could be time-limited, e.g. to start 3h before the maintenance window opens and stops displaying when the maintenance window is closing.

Another possibility I can see to implement this if the banner module could be "controlled" via the CLI or REST API in order to use external scripts.

[marc-farre]

You can control it from another module via the Module::EVENT_AFTER_GET_CONFIGURATION event.