Merge branch 'preferred-frontend' into 'develop'

Port Akkoma frontend preference code

See merge request pleroma/pleroma!4398

config/description.exs

@@ -3333,6 +3333,12 @@ config :pleroma, :config_description, [
         description:
           "A map containing available frontends and parameters for their installation.",
         children: frontend_options
+      },
+      %{
+        key: :pickable,
+        type: {:list, :string},
+        description:
+          "A list containing all frontends users can pick as their preference, format is :name/:ref, e.g pleroma-fe/stable."
       }
     ]
   },