use SubElement where possible when creating dom trees

[deichmab-draeger]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have updated the changelog accordingly.
• I have added tests to cover my changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (334d9b6) 89.69% compared to head (20e17c3) 89.69%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #285   +/-   ##
=======================================
  Coverage   89.69%   89.69%           
=======================================
  Files         115      115           
  Lines       13195    13190    -5     
=======================================
- Hits        11835    11831    -4     
+ Misses       1360     1359    -1     

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