feat: allow reordering exercises in the active workout

[armen-kocharyan]

Add Move up / Move down actions to each exercise's menu on the session screen, moving both recordedExercises and the blueprint's exercises in lockstep via new Session.withExerciseMovedUp/Down.

[github-actions]

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[armen-kocharyan]

I have accidentally pushed my commit to the main branch of my fork, as opposed to creating a new branch first.
Closed the PR to create a new one.