Timing: readout rates for power only

[tilsche]

Problem statement

Readout rates / sampling can be confusing. Readout rates are primarily important for power measurements, (true) energy measurement do not necessarily need intermediate measurements.

Suggested solution

This is related to #88 - we should address this after simplifying the sampling rate requirements.

Then it is a balance with two goals:

• Simple
• Only require what is necessary for good quality