Add copy button for planned maintenance tasks

[Simrayz]

Scope and purpose

Fixes #1613.

Add a "Create copy" action for planned maintenance tasks. This opens the create form pre-populated with the source task's description and filters, making it easy to create similar tasks without re-selecting filters manually.

This pull request

• Adds copy_from query parameter support to the create view
• Adds a dropdown menu with secondary actions (Create copy, End now, Delete) in the list view
• Adds a "Create copy" button to the detail/edit form
• Loads FontAwesome regular icons in the base template

Screenshots

Contributor Checklist

• Added a changelog fragment for towncrier
• Added/amended tests for new/changed code
• Added/changed documentation, including updates to the user manual if feature flow or UI is considerably changed
• 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
• If this results in changes in the UI: Added screenshots of the before and after

[github-actions]

Test results

    6 files    894 suites   1m 51s ⏱️
  706 tests   705 ✅ 1 💤 0 ❌
4 236 runs  4 230 ✅ 6 💤 0 ❌

Results for commit a3782df.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.71%. Comparing base (17288c0) to head (a3782df).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1813      +/-   ##
==========================================
+ Coverage   82.63%   82.71%   +0.08%     
==========================================
  Files         139      139              
  Lines        6599     6607       +8     
==========================================
+ Hits         5453     5465      +12     
+ Misses       1146     1142       -4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

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

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

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

See analysis details on SonarQube Cloud

[johannaengland]

Works beautifully! 10/10 no notes