Add module for reporting

[kais-siala]

It would be nice to have a table that provides a report after masking and weighting. The rows will be regions. Possible columns (not exhaustive):

• number of points before masking (using A_land, A_eez)
• number of points after masking
• area after weighting in km²
• mean, median, max, min, std before masking
• mean, median, max, min, std after masking
• power potential in TW peak
• energy potential in TWh before weighting and masking
• energy potential in TWh after weighting
• energy potential in TWh after weighting and masking (could be redundant, if weighting includes masking)
• sorted sample of FLH values before masking (length: 10000 pixels?)
• sorted sample of FLH values after masking (same length)
• sorted sample of FLH values after weighting (same length)

I have a Matlab script that does some of these things. Also a zonal_statistics module written in Python. They can be useful!