Add build flavors, remove some unused code

build.gradle

java/AndroidManifest.xml

java/res/layout-land/setup_steps_screen.xml

java/res/layout-land/setup_welcome_screen.xml

java/res/layout/dictionary_line.xml

java/res/layout/download_over_metered.xml

java/res/layout/more_suggestions.xml

java/res/layout/setup_start_indicator_label.xml

java/res/layout/setup_step.xml

java/res/layout/setup_steps_cards.xml

java/res/layout/setup_steps_screen.xml

java/res/layout/setup_steps_title.xml

java/res/layout/setup_welcome_screen.xml

java/res/layout/setup_welcome_title.xml

java/res/layout/setup_welcome_video.xml

java/res/layout/setup_wizard.xml

java/res/layout/suggestions_strip.xml

.../src/org/futo/inputmethod/dictionarypack/ActionBatch.java

...c/org/futo/inputmethod/dictionarypack/ButtonSwitcher.java

...tmethod/dictionarypack/DictionaryDownloadProgressBar.java