Bug 1112460 - Part III, Introduce GAIA_KEYBOARD_PRELOAD_DICT_LAYOUTS and generate config files

Bug 1112460 - Part IV, Name dictionaries with dictionaryLabel
Bug 1112460 - Part IV, Amend the build test to check the content of the zipped files
Bug 1112460 - Part V, Create tests to verify build results
DO NOT COMMIT - print content to console in checkFileContentInZip