remove sun position dependnce on pv data

[AUdaltsova]

Sun position currently lifts time off of pv data's forecast_minutes, it should instead generate the time series based off of pv's t0 and time resolution. This is needed for example to correctly run site backtest script, as currently it runs into problems at the tail end when it starts running out of pv data to have the right number of points in forecast part, and sun position ends up being the wrong shape.

This should be done for all targets, not just pv

It's not a major problem as currently this never happens in batch creation and in prod apps (as far as I know) handle that instead of datapipes, but i think it would be better for datasampler to do it robustly instead of apps doing it with hardcoded time settings. Also creates less work moving forward adding new models to apps, but might be a bit of a rehaul to get it working and remove current hack-arounds