High number of instance creation/deletion can cause DBDeadloack Error in neutron resulting creation failures.

Issue

• Neutron quota request implementation is performance bottleneck and causes outages.
• Neutron quota request implementation can end in a lock status and result in failed processing of request.
• The environment becomes unusable at a certain threshold of instance create and delete request per second due to the lock contention problem in Neutron and error DB exceeded retry limit.: oslo_db.exception.DBDeadlock is shown in neutron server logs.