Expand and collapse actions in Gantt

Gantt view previously had an "all of nothing" way to see levels of subactions. This created issues for viewing long projects or having to segment specific information.

In Gantt view, users now have the option to expand or collapse Gantt charts by level or all actions. Instead of an "expand/collapse all" option, users can choose to step through the different levels of the project.

Clicking on the current +/- buttons will expand or collapse the list by one level. Clicking on expand all/collapse all will expand or collapse the whole tree.

Thank you to Diana from Terakeet for requesting this feature!