PLT-1800 Load server side locale from the config.json (#3202)

* PLT-1800 Load server side locale from the config.json

* Add support for locales with country specifics

* Fix localization on served locale file as plain/text

* Remove github.com/cloudfoundry/jibber_jabber as vendor dependency

* Fix get locale on login_controller

glide.lock

@@ -5,8 +5,6 @@ imports:
   version: e5dc62318d9bd58682f1dceb53a4b24e8253682f
 - name: github.com/braintree/manners
   version: 82a8879fc5fd0381fa8b2d8033b19bf255252088
-- name: github.com/cloudfoundry/jibber_jabber
-  version: bcc4c8345a21301bf47c032ff42dd1aae2fe3027
 - name: github.com/dgryski/dgoogauth
   version: 67642ac6f9144f6610279e37e7be9af13f1cd668
 - name: github.com/disintegration/imaging