- removed some whitespace noise.
 - cleaned up CMakeLists.txt
 - reintegrated task_manager.c into thread-pool.c
 - cleaned up some unnecessary code

Co-authored-by: Cedric Roux <cedric.roux@eurecom.fr>
Co-authored-by: Mikel Irazabal <mikel.irazabal@openairinterface.com>

- make it clear that it belongs to OAI
- follow convention of uppercase name