Add openHAB

• The app complies with the inclusion criteria
• The original app author has been notified (and supports the inclusion)
• All related fdroiddata and rfp issues have been referenced in this merge request
• Builds with fdroid build

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Fixes rfp#430 (closed)

Successor of !2687 (closed)

Some information about the app: Release versions will be tagged with %v-release (e.g. 2.1-release). TravisCI will then bump version name (2.1), version code and fetches the latest fastlane data. After that it commits them and creates a tag %v-release-fdroid (2.1-release-fdroid).

I plan to release the beta versions with another package name (like nextcloud), but for now only stable releases should be build.

I tagged the app with UpstreamNonFree (full flavor includes non-free libs) and NonFreeAssets (The app icon and the github icons are not under a free license).