Add a method on App and Schedules to configure all schedules

[alice-i-cecile]

What problem does this solve or what need does it fill?

Changing ScheduleBuildSettings is currently very onerous: it can only be done one schedule at a time by explicitly naming it.

This is particularly troublesome with system order ambiguities, which must be denied in all schedules for certain applications that require determinism.

What solution would you like?

Add the following method to Schedules.

/// Applies the provided [`ScheduleBuildSettings`] to all schedules.
fn configure_schedules(&mut self, schedule_build_settings: ScheduleBuildSettings)

Then, mirror this method on App, calling the method on Schedules.

What alternative(s) have you considered?

We could provide a universal equivalent to edit_schedule, as seen in the example for this feature. This is more boilerplate in the common case however, and most other uses of schedule modification (like adding systems) aren't well-suited to global application.

Might be worth adding anyways, but as an additional API rather than a replacement.

[hymm]

The workaround for this currently is to do:

for (_, schedule) in app.world.resource_mut::<Schedules>().iter_mut() {
    schedule.set_build_settings(ScheduleBuildSettings {
        ambiguity_detection: LogLevel::Error,
        ..Default::default()
    });
}