[l10n] Improve Danish (da-DK) locale

[ShahrazH]

Updated Danish translations.

Some keys such as columnMenuFilter, treeDataGroupingHeaderName and groupingColumnHeaderName are a tad unclear in whether they are verbs or nouns, as their English text value are homonyms in both cases.

In addition it's unclear why the English translation for grouping is group and not grouping, as the Danish term for grouping would be gruppering but Danish term for group is gruppe if it is a noun and gruppér if it is a verb.

Same goes for filter, where the noun would be filter and the verb would be filtrer in Danish.

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