TestKit: add feature flags for bolt versions (#613)

Author: robsdedude

testkitbackend/test_config.json

@@ -31,6 +31,11 @@
     "Feature:Auth:Bearer": true,
     "Feature:Auth:Custom": true,
     "Feature:Auth:Kerberos": true,
+    "Feature:Bolt:3.0": true,
+    "Feature:Bolt:4.0": true,
+    "Feature:Bolt:4.1": true,
+    "Feature:Bolt:4.2": true,
+    "Feature:Bolt:4.3": true,
     "Feature:Bolt:4.4": true,
     "Feature:Impersonation": true,
     "Feature:TLS:1.1": "Driver blocks TLS 1.1 for security reasons",