Added Vue i18n dependency

[Vainonen]

Reasons for creating this PR

Link to relevant issue(s), if any

• Closes Add Vue i18n dependency #2030

Description of the changes in this PR

• Vue i18n dependency can be loaded from Skosmos instead loading it for each plugin separately. Dependencies from two plugins can be removed:
  https://github.com/NatLibFi/Skosmos-widget-finna
  https://github.com/NatLibFi/Skosmos-widget-suggestions/

Checklist

• phpUnit tests pass locally with my changes
• I have added tests that show that the new code works, or tests are not relevant for this PR (e.g. only HTML/CSS changes)
• The PR doesn't reduce accessibility of the front-end code (e.g. tab focus, scaling to different resolutions, use of .sr-only class, color contrast)
• The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.42%. Comparing base (24f8bfb) to head (57f3d8f).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2031   +/-   ##
=========================================
  Coverage     70.42%   70.42%           
  Complexity     1703     1703           
=========================================
  Files            34       34           
  Lines          4436     4436           
=========================================
  Hits           3124     3124           
  Misses         1312     1312           

☔ View full report in Codecov by Harness.
📢 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.

[osma]

LGTM