Implemented handshake and heartbeat

Implemented handshake in json server and handoff to endpoint

Endpoint handles connector handshake accept/decline then launches both
its IO threads alongside its heartbeat thread which contains simple
timeout logic, timeout calls connection handles to close, subsequently
killing the endpoint

test/test_endpoint_logging.py

@@ -0,0 +1,41 @@
+import logging
+from queue import Queue
+from uuid import uuid4
+
+import pytest
+
+from dynalab_core.protocols.constants import PROTOCOL_VERSION
+from dynalab_core.protocols.endpoint import ConnectorEndpoint
+from dynalab_core.protocols.errors import ConnectorEndpointQueueFullError
+from dynalab_core.protocols.packets import ProtocolMessage
+from dynalab_core.protocols.packets.handshake import ConnectorHello
+
+
+def test_full_endpoint_queue_is_logged(caplog: pytest.LogCaptureFixture) -> None:
+    hello = ConnectorHello(
+        connector_uuid=uuid4(),
+        protocol_version=PROTOCOL_VERSION,
+        connector_name="Test connector",
+        connector_version="0.1.0-test",
+    )
+    endpoint = ConnectorEndpoint(hello)
+    endpoint._packet_ingress_queue = Queue[ProtocolMessage](maxsize=1)
+
+    with caplog.at_level(logging.DEBUG, logger="dynalab_core"):
+        try:
+            endpoint.put_ingress_packet(hello)
+            with pytest.raises(ConnectorEndpointQueueFullError):
+                endpoint.put_ingress_packet(hello)
+        finally:
+            endpoint.stop()
+
+    queue_record = next(
+        record
+        for record in caplog.records
+        if getattr(record, "event", None) == "endpoint.queue_full"
+    )
+    assert queue_record.levelno == logging.WARNING
+    assert queue_record.connector_uuid == str(hello.connector_uuid)
+    assert queue_record.queue_direction == "ingress"
+    assert queue_record.queue_size == 1
+    assert queue_record.queue_capacity == 1