Privacy Panel new pull request

This is a new pull request. We had to remove the old one due to big problems with git and some Schroedinger patches....
Please, move mozL10n.get resolution to inside this function and make the API accept l10nId/l10nArgs following: https://developer.mozilla.org/en-US/Firefox_OS/Developing_Gaia/localization_code_best_practices#Writing_APIs_that_operate_on_L10nIDs

Feel free to just implement support for the shape of l10nAttrs that you need (it seems that {id:, args:} and 'l10nId' string is all you need now)