Allow configuring resampling functions and buffering options per timeseries in the `Resampler`

[leandro-lucarella-frequenz]

What's needed?

We need to be able to use different buffering options and resampling functions per timeseries/metric.

Proposed solution

Add a TimeseriesConfig object that hold these options and allow to pass options when calling add_timeseries() or in the request for the resampling actor.

We then could either remove those options from the ResamplerConfig, or we could keep them as defaults. If we do this we could provide a sentinel value for TimeseriesConfig to indicate the ResamplerConfig global value should be used (different from using a default value).

Use cases

• EVCharging
• Many more

Alternatives and workarounds

None really, creating new resamplers is not an option because we still need to get the resampled window from one resampler to get consistent sample timestamps.

Additional context

No response