Added integration tests from data-science-utils-python #141

Job	Run time
Prepare Matrix for integration tests without DB (3.8)	21s
Run test_broadcast.py	33s
Run test_gather.py	34s
Run test_multi_node_discovery.py	22m 15s
Run test_localhost_discovery.py	21m 57s
Run test_communicator.py	2m 42s
Run test_add_peer_and_wait_close.py	3m 3s
Run test_add_peer_forward_and_wait_for_peers.py	33m 38s
Run test_send_recv.py	35m 11s
Run test_add_peer_forward_and_close.py	36m 56s
Run test_add_peer_and_wait_for_peers.py	33m 43s
Run test_poll.py	40s
Run test_add_peer_and_close.py	33m 10s
	3h 44m 43s

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