♿ [#2955] A11y: Remove B-tags if they are used for styling

[jiromaykin]

B-tags should not be used lightly, usually these need to be replaced with a STRONG tag or a correct styling class, since B has no meaning and is only a visual tag (but we should use CSS for that).
Strong has emphasis in meaning and tone, which is useful to (for example) notify the user there is no data available.
Screen-reader software responds differently to B-tags and Strong tags so they are more than just a 'style'.
Issue: https://taiga.maykinmedia.nl/project/open-inwoner/task/2955

Also: it is NOT allowed to use H2 headings if that heading has no paragraph and doesn't actually summarize any content - for accessibility software Headings have a specific meaning and are read out loud as a list with nested hierarchy.

So: if there is data, then it is fine to use the H2, but if there isn't, it should be a paragraph.

Additionally we should aim to always use the NLDS classes for headings, so municipalities can overwrite these with their own tokens.

The Heading hierarchy should be correct for accessibility, and it is perfectly acceptable to use the H3 CSS style for an H2 heading, as long as the HTML structure stays correct.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.23%. Comparing base (3cb42c1) to head (121409b).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1566   +/-   ##
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  Coverage    94.23%   94.23%           
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  Files         1070     1070           
  Lines        39412    39412           
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  Hits         37140    37140           
  Misses        2272     2272           

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