feat: Implement IterationEndedSyncEvent and TimestepEndedSyncEvent

[mkundu1]

Implemented sync events for IterationEnded and TimestepEnded to execute PyFluent-side callbacks synchronously. Fluent's solution monitoring mechanism has been used for the implementation. On every solution event, Fluent streams an auto-pause event and then goes to a paused state. Upon receiving the auto-pause event, the client executes the PyFluent-side callback and then remotely resumes Fluent.

Any exception thrown in the callback is converted to a logging error to ensure Fluent resumes at the end of callback execution. Those exceptions are raised in a secondary thread, the user's script cannot react in any way to those exceptions from the primary thread. There could still be some edge cases like calling solver.exit() within the callback which will indefinitely hang Fluent.

[prmukherj]

Probably need to mark these tests to skip 22R2.