ICU is used to:
- List locales (`locales_tree`)
- Get information about those locales in different languages (`lang_tree`)
- Remove accents (`translit`)
Tracing ICU without custom data, we also load `likelySubtags` and
`metadata`. Not sure why and what happen when missing but let's be
conservatives and include them.
Make kiwix-build installable using pip.
Module is now called `kiwixbuild` because `kiwix-build` is not a valid
python identifier.
Also split toolchains in separated directory.
Matthieu Gautier