Rotation titles should be clickable and allow to edit them

[nilmerg]

At the moment a rotation can only be edited by clicking on a occurrence in the timeline.

Goal

In addition to that, a button with the cog icon should be shown in the side bar. Possibly besides the drag handle.

Implementation Hints

The interaction area of the button somewhat collides with that of the drag handle. A good compromise is required for both.

Also, remember that a title might be long enough to occupy most of the cell. Because of this, the interaction area of the drag handle and button might be static and relatively small. (Variable interaction areas are somewhat irritating.)

The mockups in the parent issue include this change.