Argus Add option to `create_fake_incident` to generate incidents from json files

trafficstars

Scope and purpose

Fixes #1451

This fixes also a bug found from #1424: To only call the management command if a source is specified.

Quite a big PR, so best review commit by commit. I did my best structuring it in a way that made sense

Contributor Checklist

Every pull request should have this checklist filled out, no matter how small it is. More information about contributing to Argus can be found in the Development docs.

[X] Added a changelog fragment for towncrier
[X] Added/amended tests for new/changed code
[X] Added/changed documentation
[X] Linted/formatted the code with ruff and djLint, easiest by using pre-commit
[X] The first line of the commit message continues the sentence "If applied, this commit will ...", starts with a capital letter, does not end with punctuation and is 50 characters or less long. See our how-to

May 20 '25 13:05 johannaengland

Codecov Report

:x: Patch coverage is 96.87500% with 2 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 79.49%. Comparing base (4c63f90) to head (610fec6). :warning: Report is 51 commits behind head on master.

Files with missing lines	Patch %	Lines
...us/dev/management/commands/create_fake_incident.py	94.87%	2 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1452      +/-   ##
==========================================
+ Coverage   79.26%   79.49%   +0.22%     
==========================================
  Files         121      121              
  Lines        5388     5417      +29     
==========================================
+ Hits         4271     4306      +35     
+ Misses       1117     1111       -6

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

:rocket: New features to boost your workflow:

:snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
:package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.