Add update-factory command

Add support for updating factory image without need to provide exact link.

schnapps.sh

@@ -161,8 +161,11 @@ Commands:
                           server.
                           Multiple types can be divided by commas.
 
-  import path             Import exported snapshot; path must point to .info file for the
-                          snapshot.
+  import [-f] path        Import exported snapshot; path must point to .info file for the
+                          snapshot. Except when importing factory image with -f option, then it
+                          has to be a tarball, but it can be an URL as well.
+
+  update-factory          Updates factory image, if the devices is supported.
 
   help                    Display this help
 
@@ -978,6 +981,14 @@ case $command in
     upload)
         upload "$@"
         ;;
+    update-factory)
+        get_board
+        if [ "$BOARD" != schnapps ]; then
+            import_sn -f "https://repo.turris.cz/hbs/medkit/$BOARD-medkit-latest.tar.gz"
+        else
+            die "Don't know what device I am, can't update my factory image"
+        fi
+        ;;
     import)
         import_sn "$@"
         ;;