compose db conn params

shared/classes/DbManager/index.js

@@ -19,19 +19,22 @@ function getConnectionConfig(obj) {
         auth.push("/?authMechanism=DEFAULT")
     }
 
-    if (DB_AUTH_SOURCE && DB_USER) {
-        auth.push(`&authSource=${DB_AUTH_SOURCE}`)
-    }
-
     auth = auth.join("")
 
-    return [
+    const params = {
-        auth,
+        auth: {},
-        {
         dbName: DB_NAME,
         useNewUrlParser: true,
         useUnifiedTopology: true,
     }
+
+    if (DB_AUTH_SOURCE) {
+        params.auth.authSource = DB_AUTH_SOURCE
+    }
+
+    return [
+        auth,
+        params,
     ]
 }