add ng-i18next support

code4hk’s site is relative small and don’t differ much in context
some design conclusion:

- use value as key( fallback gracefully for missing keys)
- use namespaces if necessary to cater different context
e.g. if “projects” should mean sth else in other pages (edge case for us)


example
`    {{ 'Drive social changes by code' | t}} `

in future a translation collaboration project /  TDN perhaps make sense, now is more than good enough


default lang is Chinese: (meanwhile we should take this setting after all Chinese is translated)

for english:
`http://localhost:8005/?setLng=en/`