Feature/4720 accessibility improvements visibility navigation

[robinmolen]

Partially Closes #4720

Changes

• The skiplink is now the first interactive element, and is shown when it has focus
• New sdk translations
• Changed the filename of the submission PDF report

Checklist

Check off the items that are completed or not relevant.

• Impact on features

  • [X] Checked copying a form
  • [X] Checked import/export of a form
  • [X] Config checks in the configuration overview admin page
  • [X] Problem detection in the admin email digest is handled

• Release management

  • [X] I have labelled the PR as "needs-backport" accordingly

• I have updated the translations assets (you do NOT need to provide translations)

  • [X] Ran ./bin/makemessages_js.sh
  • [X] Ran ./bin/compilemessages_js.sh

• Commit hygiene

  • [X] Commit messages refer to the relevant Github issue
  • [X] Commit messages explain the "why" of change, not the how

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.55%. Comparing base (2cfc111) to head (9d3b9ba). Report is 5 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4776 +/- ## ======================================= Coverage 96.55% 96.55% ======================================= Files 748 748 Lines 25399 25399 Branches 3354 3354 ======================================= Hits 24525 24525 Misses 609 609 Partials 265 265 ```

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