Refs #90.

I converted the Feature Graphic to PNG using ImageMagick:

    convert ../../../assets/play-store-feature-graphic/play-store-feature-graphic.jpg featureGraphic.png

The rest is copypasta or hard links to the Google Play Store files.

According to the F-Droid documentation [1]:

> All metadata files are completely optional,
> except for the short summary description as
> well as the longer full description.

[1] https://f-droid.org/en/docs/All_About_Descriptions_Graphics_and_Screenshots/#fastlane-structure