Add settings page

[MaHaWo]

• add settings page to the the userland tabs
• add separate component for it
• use endpoints mentioned in Add a "change my password" page #226
• currently no confirmation of changes with current password, but you have to type new pw and new email twice. that enough?

closes #226

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 83 lines in your changes missing coverage. Please review.

Project coverage is 26.50%. Comparing base (da3434f) to head (34cdbb9).

Files with missing lines	Patch %	Lines
frontend/src/lib/components/UserSettings.svelte	0.00%	72 Missing and 1 partial ⚠️
frontend/src/lib/translations.ts	0.00%	9 Missing ⚠️
frontend/src/lib/components/UserLandingPage.svelte	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #234      +/-   ##
==========================================
- Coverage   29.72%   26.50%   -3.23%     
==========================================
  Files         115      116       +1     
  Lines        4508     5056     +548     
  Branches      100      101       +1     
==========================================
  Hits         1340     1340              
- Misses       3084     3631     +547     
- Partials       84       85       +1     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
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