update ui, add metainfo

resources/li.sopht.Flashcards.metainfo.xml.in

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="desktop-application">
+  <id>li.sopht.Flashcards</id>
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>MIT</project_license>
+
+  <name>Flashcards</name>
+  <summary>Learn categories with flashcards!</summary>
+
+  <developer id="li.sopht">
+    <name>Sophie Krause</name>
+  </developer>
+
+  <url type="homepage">https://gitlab.cvh-server.de/skrause/flashcards</url>
+  <url type="vcs-browser">https://gitlab.cvh-server.de/skrause/flashcards</url>
+  <url type="bugtracker">https://gitlab.cvh-server.de/skrause/flashcards/-/issues</url>
+
+  <translation type="gettext">flashcards</translation>
+  <launchable type="desktop-id">li.sopht.Flashcards.desktop</launchable>
+  <content_rating type="oars-1.1" />
+
+  <branding>
+    <color type="primary" scheme_preference="light">#ff00ff</color>
+    <color type="primary" scheme_preference="dark">#993d3d</color>
+  </branding>
+
+  <screenshots>
+    <screenshot type="default">
+      <image>https://example.org/example1.png</image>
+      <caption>A caption</caption>
+    </screenshot>
+  </screenshots>
+</component>