[Feature] Expose global device settings to apps.

[fxb]

It would be useful for apps to be able to read some global device settings like the app cycle speed and then adjust to them.

For example, for my "Weather Map" app (https://github.com/tidbyt/community/pull/189), I would like to adjust the animation delay based on the app cycle speed, so that the full weather radar animation can finish in all cases and is not cut off if the app is shown for a shorter time.

[alan-oliv]

+1