Change time display from one item to X major Y minor

Change time display to "X major, Y minor" for all languages. I added the library "humanize-duration" for this which supports the necessary languages. The language codes are slightly different so they were changed in static/ui/languages.json.

The extra words like "in" and "ago" are not included in the library so they copied from moment JS locale and added for each language. Because the humanizeDuration function needs access to which language is selected the current language was added in the constructor as this.currentLanguage. Now that moment JS was no longer used for displaying the time some lines relating to the locale were removed.