Focus mode: Allow builders to hide and/or lock sections/pages/questions#40

When working with long workflows with multiple, complex sections/pages/questions, allow builders to hide those that have been completed so they can focus on one section at a time without worries. Alternatively, builders could divide a long workflow into mini workflows that can later be moved to the main workflow as sections/pages/sections. This could be done by grouping the miniworkflows much like tabs on Chrome can be grouped and color-coded.