add clean options in preferences

data/systemd/pamac-cleancache.service

po/pamac.pot

resources/preferences_dialog.ui

src/alpm_utils.vala

src/clean_cache.vala

src/cli.vala

src/database.vala

src/meson.build

src/preferences_dialog.vala

src/system_daemon.vala

src/transaction.vala

src/transaction_interface.vala

src/transaction_interface_daemon.vala

src/transaction_interface_root.vala