Investigate potential NFC / NFD Unicode normalization issues for composed characters (accents etc.)

[stephanegigandet]

We currently do not normalize Unicode strings, so it is very likely that some string comparisons (e.g. to match strings to taxonomies) do not work if the strings and the taxonomy entries have different normalization.

This issue is to:

• verify if we do have issues
• add test cases for those issues
• fix those issues

It may be a good thing to normalize all strings in OFF (taxonomies, database, API etc.) to a specific form.

[github-actions]

This issue is stale because it has been open 90 days with no activity.