Fix #308771: migrate invisible staff lines and line color to staffType

[elerouxx]

Resolves: https://musescore.org/en/node/308771
(Also resolves https://musescore.org/en/node/295722 )

Changes:
Migrated Invisible Staff Lines and Staff Color from Staff Properties to StaffType, and added these properties to the Staff Type Change inspector, which now allows to change staff visibility and color mid-staff.

Feedback is welcome.

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• [N/A] I created the test (mtest, vtest, script test) to verify the changes I made

[aspiers]

Awesome, thank you so much!