Implemented date localization using native Intl object.
Created special function get_localized_date_or_time_for_format
Made necessary string formatting changes in 'timerender.ts'.
Fixed tests and added some localization tests too.
Tested on my local development server, with some random languages.
Fixes#23987.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Ujjawal Modi
Anders Kaseorg
Daniil Fadeev