Add Nextcloud Deck

Hey guys :)

I'd like to ask you to add the Nextcloud Deck android app to the F-Droid-Repository.

I added metadata via fastlane (screenshots, descriptions and so on).

• Git-Repository: https://github.com/stefan-niedermann/nextcloud-deck
• Issue-Tracker: https://github.com/stefan-niedermann/nextcloud-deck/issues
• Donations via LiberaPay: https://liberapay.com/stefan-niedermann/donate
• Donations via PayPal: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=K7HVLE6J7SXXA
• Changelog will be (like Nextcloud Notes app) in the tags: https://github.com/stefan-niedermann/nextcloud-deck/tags

Regards