Feature Request: Adding a 'Feature graphic' (header image) for app stores

Hi 👋,

it's me once again. I thought it would be nice to add pictures to this project.

Googling for the typical image sizes I found the following:

• f-droid.org/en/docs/All_About_Descriptions_Graphics_and_Screenshots/
• developer.android.com/distribute/best-practices/launch/feature-graphic

I used the Hypatia logo as a basis for a header image - apparently known as 'feature graphic' with android developers.

The image is created with GIMP using a svg version of the shield icon. I also attached the XCF file to allow further modifications. hypatia-feature-graphic.xcf

According to the f-droid docs they seem a 'feature graphic' seems to be obligatory for a listing on the app's 'Latest tab'. Reading that I thought that would be great to have 😄

Hope you'll have the time to implement that!