App screenshots on the repo

[Zotl33]

I cannot use it bc i have way too old devices but i think a lot of people, including myself, would like to see screenshots from the app!

[superuser404notfound]

Done! I just added a Screenshots section to the README with the Home, Catalog (Seerr browse and request), Search and Settings screens. They show up right on the repo front page now, so you can get a feel for the app even without a compatible device. Thanks for the nudge!