Add HABPanelViewer

• The app complies with the inclusion criteria
• The original app author has been notified (and supports the inclusion) https://github.com/vbier/habpanelviewer/issues/5
• All related fdroiddata and rfp issues have been referenced in this merge request
• Builds with fdroid build

---

Fixes rfp#501 (closed)

Metadata is included in the repo: https://github.com/vbier/habpanelviewer/tree/master/fastlane/metadata/android.