Handle generation ourselves, let Scripty do extraction only
So far we let Scripty do the generation step (creation and updating of files in content and i18n folders, updating of config.yaml), using the StaticMessages.sh file. Some days ago, Scripty started putting PO files into repos directly. Since then, each time translations change, we get 2 commits: one for changes from the generation step and one for changes of PO files.
By using Messages.sh instead of StaticMessages.sh, we let Scripty do only the extraction step. The generation step will be done before each build (the build script has been updated to do this). Generated files and configs are removed in this MR, so that people who work on the repo can focus on the default language (English).