Update Locale zh-HK (#2818)

Update Locale zh-HK (#2818)

* locale: Add missing translation in zh-HK.yml

* locale: fix consistancy in zh-HK.yml translation

* locale: Improve zh-HK yml translations

* Use "PuSH" in all "PubSubHubBub" occurances.
* Simplify text on front page.
* Improve doorkeeper authorization table translations.
* Simplify setting form text for better layout.
* Improve "Business Email" translation.

* locale: Update zh-HK.json

* Fix untranslated text.
* Improve translations.