1159 add diffusive abm and smm

[jubicker]

Changes and Information

Please briefly list the changes (main added features, changed items, or corrected bugs) made:

• add diffusive ABM (model, simulation, parameters and quadwell potential)
• add SMM (model, simulation, parameters)
• add tests for both models
• add examples for both models

Merge Request - Guideline Checklist

Please check our git workflow. Use the draft feature if the Pull Request is not yet ready to review.

Checks by code author

• Every addressed issue is linked (use the "Closes #ISSUE" keyword below)
• New code adheres to coding guidelines
• No large data files have been added (files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• Tests are added for new functionality and a local test run was successful (with and without OpenMP)
• Appropriate documentation for new functionality has been added (Doxygen in the code and Markdown files if necessary)
• Proper attention to licenses, especially no new third-party software with conflicting license has been added
• (For ABM development) Checked benchmark results and ran and posted a local test above from before and after development to ensure performance is monitored.

Checks by code reviewer(s)

• Corresponding issue(s) is/are linked and addressed
• Code is clean of development artifacts (no deactivated or commented code lines, no debugging printouts, etc.)
• Appropriate unit tests have been added, CI passes, code coverage and performance is acceptable (did not decrease)
• No large data files added in the whole history of commits(files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• On merge, add 2-5 lines with the changes (main added features, changed items, or corrected bugs) to the merge-commit-message. This can be taken from the briefly-list-the-changes above (best case) or the separate commit messages (worst case).

closes #1159

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.16%. Comparing base (34a0277) to head (c04573b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1162      +/-   ##
==========================================
+ Coverage   97.13%   97.16%   +0.02%     
==========================================
  Files         149      154       +5     
  Lines       13999    14210     +211     
==========================================
+ Hits        13598    13807     +209     
- Misses        401      403       +2     

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[reneSchm]

I seem to barely document code I write under a deadline. I will continue this with more suggestions later, but feel free to edit them - or add your own documentation, there is a lot to do...

The directory structure and naming looks pretty good. I have not checked the tests yet