Secure NumberOfPVBlocks implementation

Summary

There was an issue in PV_Configuration_3D.create_block_of_panels() (#162 (closed)) with the number of panels being instantiated, related to known behavior of numpy.arange().

This problem is more than likely also present in the create_central() method since they share similar implementations.

Steps to reproduce

By changing the value of NumberOfPVBlocksX and Y to various numbers in the Example1_AV.yaml file.

Possible fixes

the problem lies in MODULES.PHOTOVOLTAICS.configuration.PV_Configuration_3D.create_central().

Possible fixes

• See fix by Julien Philippart in !56 (merged).
• add unit tests