Optional PII logging (#11322)

* Start with logger

* allow user to enable PII logging

* prefix the log

extensions/azurecore/package.json

@@ -92,6 +92,11 @@
             "default": true,
             "description": "%config.noSystemKeychain%",
             "when": "isLinux || isWeb"
+          },
+          "azure.piiLogging": {
+            "type": "boolean",
+            "default": false,
+            "description": "%config.piiLogging%"
           }
         }
       }