Implement Pub/Sub & Notifier/Listener integration-tests that are highly concurrent

[elfenpiff]

Brief feature description

Multiple bugs were raised due to the lack of concurrent communication tests. We need tests that cover:

• sending/receiving messages from within different threads
• many publisher reconnect to one subscriber
• many subscriber reconnect to one publisher
• create/open all service types concurrently
• many listener reconnect to one notifier
• many notifier reconnect to one listener
• write tests for shared memory with pool allocator
  • allocate on one side, translate pointer, write on other side - whole shm
  • offset must start at 0 and must always be a multiple of the bucket size
• write full test suite for shm pool allocator
• publisher/subscriber reconnect and updates history after reconnect
• drop(subscriber), keep sample
  • blocks max subscriber
  • sample can be read and no data race
• drop(publisher), keep sample on receiver side
  • blocks max publisher
  • sample can be read
• drop(publisher), keep sample on publisher side
  • blocks max publisher
  • sample can still be published but will not be received unless multiple samples on publisher side are hold
• drop(publisher & subscriber), keep sample
• drop(service), keep ports
  • communication shall still work
  • service no longer discoverable
  • when service recreated and ports are added, existing ports shall receive/can send to old ports