[#4418] Add addressNl specific mappings to Objects API registration (variables tab)

[vaszig]

Closes #4418

Changes

This PR handles the frontend part of the task

• Added specific addressNL fields/mappings to the Objects API registration (backend-frontend)
• Added stories

Checklist

Check off the items that are completed or not relevant.

• Impact on features

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

• Release management

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

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

  • Ran ./bin/makemessages_js.sh
  • Ran ./bin/compilemessages_js.sh

• Commit hygiene

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

[codecov]

Codecov Report

Attention: Patch coverage is 97.43590% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.57%. Comparing base (22d641b) to head (44a63cd).
Report is 59 commits behind head on master.

Files with missing lines	Patch %	Lines
...ons/contrib/objects_api/submission_registration.py	93.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4751      +/-   ##
==========================================
+ Coverage   96.55%   96.57%   +0.01%     
==========================================
  Files         748      748              
  Lines       25413    25480      +67     
  Branches     3358     3375      +17     
==========================================
+ Hits        24538    24607      +69     
+ Misses        610      608       -2     
  Partials      265      265              

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[vaszig]

FYI, we have to take into consideration the old forms that they already may have addressNL variable_mappings configured. We may need a data migration for this.