knowledge service (#367)

* Write knowledge core elements to Cassandra

* Store service works, building management service

* kg-manager

test-api/test-knowledge-fetch

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+
+import requests
+import json
+import sys
+import base64
+import time
+
+url = "http://localhost:8088/api/v1/"
+
+############################################################################
+
+input = {
+    "operation": "fetch-kg-core",
+    "id": "https://trustgraph.ai/doc/intelligence-and-state",
+    "user": "trustgraph",
+}
+
+resp = requests.post(
+    f"{url}knowledge",
+    json=input,
+)
+
+print(resp.text)
+resp = resp.json()
+
+print(resp)
+
+if "error" in resp:
+    print(f"Error: {resp['error']}")
+    sys.exit(1)
+
+# print(resp["response"])
+print(resp)
+
+sys.exit(0)
+
+############################################################################
+