add script to pull translation from transifex

bigbluebutton-html5/private/locales/bg_BG.json

bigbluebutton-html5/private/locales/de.json

bigbluebutton-html5/private/locales/en.json

bigbluebutton-html5/private/locales/es_ES.json

bigbluebutton-html5/private/locales/fr.json

bigbluebutton-html5/private/locales/id.json

bigbluebutton-html5/private/locales/ja.json

bigbluebutton-html5/private/locales/ja_JP.json

bigbluebutton-html5/private/locales/km.json

bigbluebutton-html5/private/locales/pt_BR.json

bigbluebutton-html5/private/locales/ru_RU.json

bigbluebutton-html5/private/locales/uk_UA.json

bigbluebutton-html5/transifex.sh