Add multi language support

Konstantin Zhukovrequested to merge
add-multilang-support into v1
  • add UI-component localeSwitcher
  • implement URL-based locale handling;
  • setup react-intl and add localisation to visible template components (umbrella-header, search, accessible languages);
  • update acccessabilityLanguage component to support locales in URL;
  • replace Apache 2.0 license with MIT in some components affected by this task;

Suggestions for improvement:

Consider moving the react-intl IntlProvider (including language imports and
mapping) from the layout into a dedicated wrapper component, e.g. withIntlProvider.

Merge request reports