Add the capability to read, filter and generate a new surface source file

[zoeprieto]

Description

surf_source_write can record particle files on different surfaces, or crossing in both directions, etc. These surface source files can be used to decouple geometries in Monte Carlo simulations. For this it is of interest to study and filter the particles on a particular surface, in some direction or in some area of the surface, so it can be useful to add the capability in OpenMC to read, filter the particles and generate a new source.

Alternatives

Do nothing, this implies that the user has to generate his own tool or use an external tool such as MCPL or KDSource
Incorporate basic tools for reading, filtering and writing surface source files in OpenMC.

Compatibility

Create a SourceParticles class as a list of SurfaceParticle to handle the file in the Python API.