EXOGTN-1815 Add supported-locale for I18NMessage.js and UIGadget.js

Fix description:
* I18NMessage.js generates the i18n labels for GateIn's Date Time Picker and Save, Cancel buttons when editing a gadget's setting
* UIGadget.js generates the i18n label for the confirmation when deleting a gadget.
Merge commit 'e9349819086ab1076a1c77540d8b4bb4928c0220' into HEAD
Merge remote-tracking branch 'remotes/origin/feature/4.0.x-translation' into feature/4.0.x-translation-jipt