Bug 1112460 - Part I, Remove v2 placeholders in keyboard build script
Bug 1112460 - Part II, Allow GAIA_KEYBOARD_LAYOUTS=*,noPreloadDictRequired
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 of different config
Merge pull request #26839 from timdream/keyboard-dyn-build

Bug 1112460 - Keyboard build script changes to optionally preload dict, r=mnjul, gduan