[MU3] Move soloist section in Orchestra

[njvdberg]

Move soloist section in Orchestra above choir to make sure vocal soloists are always above the choir.

In case a score has both vocal and instrumental soloists, the instrumental soloist is at the wrong place and should moved manually to the right position in the score.

The intention is to come with a flexible definition of soloist locations in a future version.

Resolves: https://trello.com/c/3Oa4SG5R/27-solo-singers-should-go-above-all-other-singers-in-orchestral-ordering

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