Enable linking SCORE run to CK Board project

[vkorir]

Enable linking SCORE run to CK Board projects

• Verify only valid join codes are accepted
• Verify linking/unlinking works after run creation confirmation, and run setting dialog
• Verify added shared teacher owner is also added to linked CK project
• Verify teacher to whom a run is transferred to is added to linked CK project
• Verify students who join a run are added to linked CK project
• Verify student removed from a run is also removed from linked CK project

Closes #470