Make data fetch time interval changeable via state variable

[Loenne83]

Problem:
Sometimes, a more precise time resolution of the data is helpful. Changing of the data fetch time interval is currently only possible by changing instance config.

Possible solution:
The instance may provide a read/writable variable as state in objects. This variable can be modified with scripts in order to get more detailled data for a short period of time

Alternative:
A variable that - when set to true - instantly causes the instance to fetch current data.