Introduce ParticleList class for manipulating a list of source particles

[zoeprieto]

Description

This is a preliminary solution to the issue #3147 for reading, filtering, and generating new surface source files. It is a first approach to post-processing of surface sources.
A SourceParticles class is created as a SourceParticle list for handling source particles in the Python API.

Fixes #3147

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[paulromano]

@zoeprieto I did a bit of refactoring on this branch. Let me know what you think of the changes and if you are happy, please go ahead and add some tests and then we can get this merged in. Thanks!

[zoeprieto]

Thank you @paulromano for the changes, now it is definitely clearer. I added some tests as a first proposal. Let me know if you are ok with where I put them and if any extra tests should be added.

[paulromano]

All set now; thanks for the tests!