More flexible boxes

Description

Add new OOP implementation of boxes. This includes two abstract classes:

• the base class
• a class for shapes

Then there are currently four derived classes from the above:

• spheres
• cylinders
• parallelepipeds
• an union or intersection of boxes

These new classes are used in the local multipoles utilities and they replace and old implementation. New types of boxes will follow soon.

News snippet

New OOP implementation for boxes.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.