Use infer_limits parameter for clearsky.reno, and accept POA irradiance.

[cwhanse]

features.clearsky.reno relies on pvlib's detect_clearsky function. That function was enhanced by adding capability to infer parameter from the time resolution of the input data. The same work showed that the clearsky identification method applies to time-averaged data out to 30 minutes, and to POA irradiance.

1. Add infer_limits=True to features.clearsky.reno's call to the pvlib function.
2. Edit the docstring to clarify that the method can be applied to POA irradiance and to time-averaged data at up to 30-minute intervals.
3. Consider replacing current reference [2] (B. H. Ellis et al.), which is the source of current parameters, with Jordan and Hansen reference from the pvlib function. The current parameters would be superceded by infer_limits.