Add a filter for items displayed in gantt view (version, issues)
When managing many projects, sometimes you'd just like to see versions coming without any issue in gantt global view. It's not possible unless you have a dumb filter to remove all issues.
It would be good to have a filter (maybe checkboxes on top of issues filters? or in the sidebar like activity page?) to say which type of items you want to see. Same goes for calendar maybe, but I don't use it much so I may be mistaken.
I don't know if it would be problematic with #6276 (Gantt chart rewrite), Eric ?