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

Brief feature description

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

[x] sending/receiving messages from within different threads
[x] many publisher reconnect to one subscriber
[x] 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