Add API document and its generating util (pingcap#1929)

.gitignore

@@ -39,3 +39,5 @@ kubeconfig
 /output/
 # kubetest2 default artifacts directory
 /_artifacts/
+
+.DS_Store

docs/api-references/config.json

@@ -0,0 +1,29 @@
+{
+  "hideMemberFields": [
+    "TypeMeta"
+  ],
+  "hideTypePatterns": [
+    "ParseError$",
+    "List$",
+    "DataResource"
+  ],
+  "externalPackages": [
+    {
+      "typeMatchPrefix": "^k8s\\.io/apimachinery/pkg/apis/meta/v1\\.Duration$",
+      "docsURLTemplate": "https://godoc.org/k8s.io/apimachinery/pkg/apis/meta/v1#Duration"
+    },
+    {
+      "typeMatchPrefix": "^k8s\\.io/(api|apimachinery/pkg/apis)/",
+      "docsURLTemplate": "https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.13/#{{lower .TypeIdentifier}}-{{arrIndex .PackageSegments -1}}-{{arrIndex .PackageSegments -2}}"
+    },
+    {
+      "typeMatchPrefix": "^github\\.com/knative/pkg/apis/duck/",
+      "docsURLTemplate": "https://godoc.org/github.com/knative/pkg/apis/duck/{{arrIndex .PackageSegments -1}}#{{.TypeIdentifier}}"
+    }
+  ],
+  "typeDisplayNamePrefixOverrides": {
+    "k8s.io/api/": "Kubernetes ",
+    "k8s.io/apimachinery/pkg/apis/": "Kubernetes "
+  },
+  "markdownDisabled": false
+}