test(e2e): Verify different credentials are brokered to target (#3149)

* test(e2e): Verify json credentials are brokered back

* test(e2e): Get expected json credentials from file

* test(e2e): Check private key credentials are brokered to target

* test(e2e): Regenerate test .pem file for every test

testing/internal/e2e/tests/static/testdata/credential.json

@@ -0,0 +1,4 @@
+{
+    "username": "name-json",
+    "password": "password-json"
+}