When no objects are selected the 3dcursor should be movable with the gizmo/manipulator

This would make it easier to place the 3d cursor for some operations and tools. For example the spin tool uses the 3d cursor as pivot so this makes it easier to line it up in 3d. This also helps with object spawning as you can easily move the 3d cursor for example 2 meters up.

This also brings up the question should the 3d cursor be rotatable and scalable? That way you could add objects with those orientations and scales already on the object.