Fix to break semaphore circular dependency

[jackyalbo]

Explain the changes

1. We found a circular dependency in our code between: promise -> semaphore -> wait_queue -> promise
2. We want to handle in 2 ways:
   2.1 We wont import the whole promise module into wait_queue - we will take defer out and create new class to be imported
   2.2 As semaphore was create as empty object due to this issue - we won't import dircectly semaphore object in our code but will import its parent file which will allow the object to be loaded in case of future circular dependencies involving this module.

Issues: Fixed #xxx / Gap #xxx

1. Fixed https://issues.redhat.com/browse/DFBUGS-1471

Testing Instructions:

1. Ensure you don't see any "Semaphore is not a constructor" in our logs.

• Doc added/updated
• Tests added