Adding semaphore usage on the '/run' endpoint (#8526)
### What problem does this PR solve?
Switching threading.Lock() to asyncio.Lock(), since threading.Lock() is
blocking.
### Type of change
- [x] Performance Improvement
### What problem does this PR solve?
Add code_executor_manager. #4977.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)