Ability to create and pin project folders

We've now added the ability to add projects to folders that can be pinned to the left hand sidebar, displaying project hierarchy in the pinned section.

Users can still pin child projects to have them displayed at the top level. When a user pins a parent project, the entire project tree below the parent will be added to the pinned section and collapsed, same as how it appears in the Projects section of the left bar.

Thank you to David at City of Mesa, Christopher at Signature Hardware and Courtney at Wuffes for voting on this feature!