Boosts & Speed- and Sales Bells

There are three main ways to temporarily increase the productivity of a factory:
 * Boosts (temporary multipliers that increase the production of the active factory by a certain amount)
 * Speed- and Sales Bells (can be unlocked in the Research Tree and speed up the Warehouse- and Market Workers of the active factory respectively)
 * Ad-Boosts (Advertisement Videos that can be watched to boost all production in a factory or district for a certain amount of time)