Add Traditional Chinese, Hong Kong translation (zh-HK) (#1544)

Add Traditional Chinese, Hong Kong translation (zh-HK) (#1544)

* Added Chinese Traditional Hong Kong (zh-HK) for Ruby

* Added translations for Ruby.

* Added Chinese Traditional Hong Kong (zh-HK) for JS

* Added translations for javascript code.

* Rearrange language references in mastodon.jsx

* Break `addLocaleData` into multiple lines. Make future commit more readable.
* Roughly re-sort the languages in alphabetical orders
  (only manually put English on top because it is default).

* Sort application.rb locale with alphabetical order

With exception that English (default language) goes first.
Improve code readability.

* Resort language selection box alphabetically

Sort HUMAN_LOCALES in the alphabetical order of display name
(except English, the default language, come first).

Improve usability.