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-response.json

@@ -0,0 +1,51 @@
+{
+    "interval": "*/2 * * * *",
+    "strategy_uuid": "6b3b3902-8508-4cb0-bb85-67f32866b086",
+    "goal_uuid": "e1a5a45b-f251-47cf-9c5f-fa1e66e1286a",
+    "name": "test_audit",
+    "parameters": {
+        "host_choice": "retry",
+        "granularity": 300,
+        "thresholds": {
+            "cpu_util": 0.2,
+            "memory.resident": 0.2
+        },
+        "periods": {
+            "node": 600,
+            "instance": 720
+        },
+        "retry_count": 1,
+        "metrics": [
+            "cpu_util"
+        ],
+        "weights": {
+            "cpu_util_weight": 1.0,
+            "memory.resident_weight": 1.0
+        },
+        "instance_metrics": {
+            "cpu_util": "compute.node.cpu.percent",
+            "memory.resident": "hardware.memory.used"
+        }
+    },
+    "auto_trigger": false,
+    "uuid": "65a5da84-5819-4aea-8278-a28d2b489028",
+    "goal_name": "workload_balancing",
+    "scope": [],
+    "created_at": "2018-04-06T07:27:27.820460+00:00",
+    "deleted_at": null,
+    "state": "PENDING",
+    "audit_type": "CONTINUOUS",
+    "links": [
+        {
+            "rel": "self",
+            "href": "http://controller:9322/v1/audits/65a5da84-5819-4aea-8278-a28d2b489028"
+        },
+        {
+            "rel": "bookmark",
+            "href": "http://controller:9322/audits/65a5da84-5819-4aea-8278-a28d2b489028"
+        }
+    ],
+    "strategy_name": "workload_stabilization",
+    "next_run_time": null,
+    "updated_at": null
+}