Add categories: "AudioVideo;Audio;" to metadata

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>
Add translation functions

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>
Update signature of WebApp._onInitAppRunner

Signed-off-by: Jiří Janoušek <janousek.jiri@gmail.com>