Add prometheus, alertmanager, pushgateway configs

Change-Id: I7f146e0207ada58f0723b14d0a625a6bce67ea9f
diff --git a/tests/pillar/prometheus_pushgateway.sls b/tests/pillar/prometheus_pushgateway.sls
new file mode 100644
index 0000000..7921ba1
--- /dev/null
+++ b/tests/pillar/prometheus_pushgateway.sls
@@ -0,0 +1,3 @@
+prometheus:
+  pushgateway:
+    enabled: true