Internationalization

**Is your feature request related to a problem? Please describe.**
I want Voyager to be localized to my native language and I'm ready to contribute into translation.

**Describe the solution you'd like**
Adopt some robust i18n framework, e. g. react-i18next. I18n framework must support at least multiple plural forms in translations, so please do not consider simple dict approach.

**Additional context**
It also would be nice if you integrate your repo with weblate or some other friendly web-based translation UI.