Feature: insertion of cloned measures (including frames)

I noticed in the past there were multiple feature requests for being able to copy time signatures etc, but later I considered "deep copying" so that I can clone a section and get it somewhere else in the score.... or get it from another score

Code could use a clean-up, and it is bound to "clone" instead of being able to just paste into existing measures, but here's a demonstration of working examples:

001 - Basic copy paste clone.webm

Found a problem existing in 3.6.2 when there are two clefs back-to-back (one in measure then next before a chordrest)... the measure clef gets lost and replaced with a duplicate (but then again, it's absurd to have two different ones there, so whatever) The problem is worse when cloning because the second-clef is cloned, so the result is having two treble clefs. Whatever. User can fix that if for some weird reason that circumstance arises.

One nice thing about this idea is being able to bring information from another score more holistically, and quickly. For example (entire score) (can't do the whole thing in one action because range-selection requires to start and end on a musical measure... but in between if there are frames,... they do copy/paste, although that isn't shown in these videos):

03 from score.webm

Or like a portion of some sort:

portion.webm

Hopefully can make a PR later to provide for 3.7 users and get some feedback or extra testing for it ;)

Jojo-Schmitz / MuseScore

Feature: insertion of cloned measures (including frames) #638