Queue RushTI Executions

[MariusWirtz]

Introduce an alternative run mode that avoids overlapping RushTI executions.

So when RushTI is called to run with n threads by two separate callers at approximately the same time, execution two should queue and only start after execution one is completed.

This avoids the situation that n*2 threads are running in TM1 and potentially overwhelm the TM1 server.