I18n case insensitive search

[akirashirosawa]

Summary

SUMMARY: Bugfixes "Case insensitive search for non-latin characters"

Purpose of change

Fixes #21566 (and my duplicate #32999)
Finalizes PR #26983 (by @AMurkin)

Describe the solution

1. Set global locale by the language settings, and update when language changed.
2. Catch exception when locate is not available in system (for example es_AR is not available for my macOS), and in this case set en_US.
3. If locale is not en_US - use facet of locale for locale-specific tolower.

With all recipes available (from debug menu) - I didn't notice changes in the search speed, even with full description search.

Russian example (KATANA aka КАТАНА)

Polish example (GOLD aka ZŁOTO)

)

English works as before, without changes and unnecessary string converts.

Describe alternatives you've considered

Additional context