Add a way to get the resampled `microgrid.frequency`

[llucax]

What's needed?

microgrid.frequency is the only high-level interface that's not resampling, because usually this value is needed as realtime as possible. But still there are times where we might need to resample it.

Proposed solution

We mentioned to add a resample: bool optional parameter, and maybe adding this as a standard to all metrics.

Use cases

For example, if we need to feed the frequency to ML models, in that case it should be aligned to the same timestamp as the rest of the data.

Alternatives and workarounds

No response

Additional context

No response

[llucax]

Given the last talks, I would just always use resampled data for the frequency. The global resampling period should be small enough so that it could be used as real-time data.

[llucax]

VoltageStreamer is also using un-resampled data.