Various bug fixes and improvements
In particular, this ensures the available languages are consistent in every part of the website, and paves the way to define per-page language information (including script direction). Also adds a check for broken links that is logged during the build and available in GitLab pipelines.
- 3e3f6c6d - Remove forgotten vestiges of Khmer locale and glossary page.
- 163d65a7 - Makefile: ensure PO file timestamps are always updated.
- e098ecde - Use a single source of locale data everywhere.
- b395355d - Update libraries.
-
599c6ab6 - Add
metalsmith-broken-link-checker
plugin. - b34dbe3d - Copy media as part of the build, so they are not considered broken links.