Follow-Up for Multi-Resolution Support

[philippotto]

See #4755

• improve labeling performance (labelVoxelInAllResolutions labels each voxel individually and then also for each mag). consider using LabeledVoxelsMap to batch bucket updates and also directly use their upsampling/downsampling methods
• the fill-tool only fills the current slice which does not match the behavior of the normal brush
• Brush preview can be imprecise #7128
• Brush preview can be imprecise when brushing in higher mag
• mag restriction only restricts creating new nodes. e.g., deleting a node in a restricted mag is still possible which is a bit inconsistent. not super high-pri and also not super clear how to solve this optimally. deleting a tree should probably be possible in all mags, since it can be done via the trees tab.
• Refactoring:
  • LabeledVoxelMap could hold more meta information
  • zoomedAddressToAnotherZoomStep should be replaced by zoomedAddressToAnotherZoomStepWithInfo (afterwards, the naming can be shortened probably). We need to be careful here, since the old code could also convert to not existing mags. Often, this should not be necessary, but it needs to be checked on a case-by-case basis.

Feel free to add more.