Rename the "Locale" sub package to "i18n"
The Locale package will eventually contain more functionality than just handling the locale and CLDR. It also offers means to translate labels and otherwise localize FLOW3 applications. Therefore this sub package is really about internationalization.
[~TASK] FLOW3 (I18n): Renamed Locale subpackage directory name to I18n. Relates to #8772.
[~TASK] FLOW3 (I18n): Renamed Locale subpackage to I18n (completed). Resolves #8772.
[+BUGFIX] FLOW3 (I18n): Changed name Locale to I18n in configuration. Relates to #8772.