TASK: Remove deprecated singular node operations

[grebaldi]

@grebaldi in #3822:

• I have added deprecation markers to all singular node operations (stuff like copy as opposed to copyMultiple, move as opposed to moveMultiple and so on)
  • While I was attempting to fix Moving nodes with Preset Nodetype filter #2800, I stumbled upon this confusion, and since all singular operations can just as well be expressed as multiple operations, we should drop the singular ones entirely
  • Follow up to this PR: The operations should be removed in 9.0 (this will require additional work)