Forms for incident list refresh info

[hmpf]

Scope and purpose

Replaces #1385
Fixes #1382
Depends on #1512

Adds consistency and validation to ALL recognized GET-parameters on the incident list page.

With Django 5.2 we could go a step further in cleaning up this, some code taken from #1385. There should be no visible changes or changes to UX.

First step is #1512

Contributor Checklist

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More information about contributing to Argus can be found in the
Development docs.

• Added a changelog fragment for towncrier
  • invisible change, just slighter higher security
• Added/amended tests for new/changed code
• Added/changed documentation, including updates to the user manual if feature flow or UI is considerably changed
  • invisible change
• Linted/formatted the code with ruff and djLint, easiest by using pre-commit
• 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
• If applicable: Created new issues if this PR does not fix the issue completely/there is further work to be done

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
1 Accepted issue

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 85.43689% with 15 lines in your changes missing coverage. Please review.

Project coverage is 79.54%. Comparing base (624527f) to head (69b0f5e).

Files with missing lines	Patch %	Lines
src/argus/htmx/incident/views.py	84.48%	9 Missing ⚠️
src/argus/htmx/incident/filter.py	71.42%	4 Missing ⚠️
src/argus/htmx/incident/forms.py	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1514      +/-   ##
==========================================
+ Coverage   79.46%   79.54%   +0.08%     
==========================================
  Files         121      122       +1     
  Lines        5425     5511      +86     
==========================================
+ Hits         4311     4384      +73     
- Misses       1114     1127      +13     

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[johannaengland]

Just to make it more explicit that timeframe is in minutes

Suggested change

	after = tznow() - timedelta(seconds=timeframe * 60)
	after = tznow() - timedelta(minutes=timeframe)