Allow a content type only once (Only One) (8.x-1.10) - en to eu translation catalogue (6 entries)

en: Content
eu: Edukia

en: Disabled
eu: Ezgaituta

en: Settings
eu: Ezarpenak

en: About
eu: (r)i buruz

en: Uses
eu: Erabilerak

en: Creating content
eu: Edukia sortzen
