Enable datasets: NSRDB and Solcast

[euronion]

Enable the use of NSRDB and Solcast datasets for cutout creation.

Detailed Description

• The PSM (Physical Solar Model) from NSRDB is expanding to near global coverage, see: https://nsrdb.nrel.gov/ .
• Alternatively the commercial Solcast dataset might be of interest, see https://solcast.com , which offers free public researcher credits (https://solcast.com/solar-data-api/free-solar-radiation-historical-and-forecasting-data-for-researchers/)

Context

SARAH and ERA5 have some shortcomings in term of technologies used/parameters considered/spatial resolution/temporal resolution. These shortcoming may be compensated by these datasets.