Add option for mirrored diagrams for left-handed players

[KCarlile]

Background

Left-handed players would like a mirrored diagram, so this should be an option when creating diagrams. It would also be great if there was an option to flip all the diagrams on a page or per diagram.

Acceptance Criteria

• Creators can specify that the diagram should be mirrored for vertical or horizontal diagrams
• If global diagram controls become a feature (Allow for global (page-level) configuration options #7), then global mirroring should be an option for left-handed players to flip all the diagrams on a page

Approach

• TBD

Notes

TBD