Add API Reference for Watcher

This patch set adds API Reference along with some
fixes to documentation. It partially fixes bug #1757423.

Change-Id: I107b4fd5daf40aad63fc13864debbbbc82a9826c

api-ref/source/samples/audit-create-request-continuous.json

@@ -0,0 +1,12 @@
+{
+    "auto_trigger": false,
+    "audit_template_uuid": "76fddfee-a9c4-40b0-8da0-c19ad6904f09",
+    "name": "test_audit",
+    "parameters": {
+        "metrics": [
+            "cpu_util"
+        ]
+    },
+    "audit_type": "CONTINUOUS",
+    "interval": "*/2 * * * *"
+}