* i18n fixes
- fix issue with default (fallback) language set to browser language
- fix issue with fallback language loading when browser language set to
non-English locale
* code and UI fixes
- move document list i18n strings into own scope
- replace MDL menu with @angular/material menu (fixes issue with menu
items translation, not supported by MDL)
- minor improvements
* fix unit tests
* improve i18n docs and code
- provide basic documentation for Translation service
- remove custom Login component localisation in favour of documentation
sample
- simplified i18n setup for demo shell (single path for dev/prod env)
* remove unnecessary comments
