feat: implement localization system (#716)

* lib/localization: implement localization system

Locale files are placed in lib/localization/locales/. If you add a
locale, update manifest.json with available locales.

* Exclude locales from check spelling

* tests(lib/localization): add comprehensive translations test

Signed-off-by: Xe Iaso <me@xeiaso.net>

* fix(challenge/metarefresh): enable localization

Signed-off-by: Xe Iaso <me@xeiaso.net>

* fix: use simple syntax for localization in templ

Also localize CELPHASE into French according to the wishes of the
artist.

Signed-off-by: Xe Iaso <me@xeiaso.net>

* chore: spelling

Signed-off-by: Xe Iaso <me@xeiaso.net>

* chore:(js): fix forbidden patterns

Signed-off-by: Xe Iaso <me@xeiaso.net>

* chore: add goi18n to tools

Signed-off-by: Xe Iaso <me@xeiaso.net>

* test(lib/localization): dynamically determine the list of supported languages

Signed-off-by: Xe Iaso <me@xeiaso.net>

---------

Signed-off-by: Xe Iaso <me@xeiaso.net>
Co-authored-by: Xe Iaso <me@xeiaso.net>

.gitignore

@@ -20,3 +20,5 @@ node_modules
 
 # how does this get here
 doc/VERSION
+
+web/static/locales/*.json