fix #309066 + fix #283996: the same headers/footers are used for the score and all its parts (4.x)

[SKefalidis]

Resolves: https://musescore.org/en/node/309066, https://musescore.org/en/node/283996

Moved headers/footers from the Movements class to Score.

• I signed CLA
• I made sure the code in the PR follows the coding rules
• I made sure the code compiles on my machine
• I made sure there are no unnecessary changes in the code
• I made sure the title of the PR reflects the core meaning of the issue you are solving
• I made sure the commit message(s) contain a description and answer the question "Why do those changes fix that particular issue?" or "Why are those changes really necessary as improvements?"
• I made sure the commit message title starts with "fix #424242:" if there is a related issue
• [n\a] I created the test (mtest, vtest, script test) to verify the changes I made

[Jojo-Schmitz]

Note to self: #6450 for 3.x

[SKefalidis]

@anatoly-os this is the master version of #6450

[Jojo-Schmitz]

#6450 got manually merged into master so this here is no longer needed