944 streamline secir python code

[MaxBetzDLR]

Changes and Information

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

• Change depreciated module name of secir model in python package
• Improve continuity of code structure and naming
• Update documentation
• Script to check missing/old license
• Check and update current examples

If need be, add additional information and what the reviewer should look out for in particular:

-

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

• [x] Every addressed issue is linked (use the "Closes #ISSUE" keyword below)
• [x] New code adheres to coding guidelines
• [x] No large data files have been added (files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• [x] Tests are added for new functionality and a local test run was successful (with and without OpenMP)
• [x] Appropriate documentation for new functionality has been added (Doxygen in the code and Markdown files if necessary)
• [x] 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)

• [x] Corresponding issue(s) is/are linked and addressed
• [x] Code is clean of development artifacts (no deactivated or commented code lines, no debugging printouts, etc.)
• [x] Appropriate unit tests have been added, CI passes, code coverage and performance is acceptable (did not decrease)
• [x] No large data files added in the whole history of commits(files should in sum not exceed 100 KB, avoid PDFs, Word docs, etc.)
• [x] 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 #944

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.23%. Comparing base (575a146) to head (307c401).

:exclamation: Current head 307c401 differs from pull request most recent head 3443466

Please upload reports for the commit 3443466 to get more accurate results.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1041 +/- ## ======================================= Coverage 96.23% 96.23% ======================================= Files 128 128 Lines 10852 10852 ======================================= Hits 10443 10443 Misses 409 409 ```

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