Dutch grammar fixes and rephrasings

[ebbez]

• Replaced words that were probably meant as verb but are interpreted as noun in Dutch language with the verb-form ('Export'/'Import' => 'Exporteer'/'Importeer').
• Rephrased some confirmation sentences ("Really delete X?") that are phrased weirdly in Dutch. Replaced them with phrasing "Are you sure you want to delete X?".
• Replaced all "formal"/distant you/your (u/uw) with the already more occurent "informal"/personal you (je/jouw).
• Compounded some nouns

[berry120]

Thank you!