[LANGUAGE] Use setlocale to set the locale to support non-ascii environments

[gynt]

I am not sure if we should set utf-8 or the users local locale.
https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/setlocale-wsetlocale?view=msvc-160&viewFallbackFrom=vs-2019#utf-8-support

This requires a slight rewrite of how the extension store is set up, because currently it does an IO operation in the constructor. This needs to be moved to somewhere else in order to allow setlocale to happen before initial IO operations.

[gynt]

https://learn.microsoft.com/en-us/cpp/build/reference/utf-8-set-source-and-executable-character-sets-to-utf-8?view=msvc-170

https://stackoverflow.com/questions/30829364/open-utf8-encoded-filename-in-c-windows