[ZEPPELIN-5445] Allow users to access the spark UI outside the kubernetes cluster

### What is this PR for?
Currently, when zeppelin server is running outside of k8s cluster, users cannot access the spark UI directly from the web page of Zeppelin. So this PR creates ingress resource in `k8s/interpreter/100-interpreter-spec.yaml` and enables the `SPARK JOB` button to jump directly to the URL defined by ingress.

If user does not specify the property `zeppelin.spark.uiWebUrl`, it will be automatically generated according to the template: `{{PORT}}-{{SERVICE_NAME}}.{{SERVICE_DOMAIN}}`, which is also the URL that the `SPARK JOB` button points to. So this PR also configured the ingress.host by this URL.

This PR also adds a property `zeppelin.k8s.spark.useIngress` to let user choose whether to create ingress.
Example usage:
```
zeppelin.k8s.spark.useIngress true
```

### What type of PR is it?
[Improvement]

### Todos
* [ ] - Task

### What is the Jira issue?
* <https://issues.apache.org/jira/browse/ZEPPELIN-5445>

### How should this be tested?
* CI pass and manually tested

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No

Author: rick <rick@rickdeMacBook-Pro.local>

Closes apache#4176 from rickchengx/ZEPPELIN-5445 and squashes the following commits:

fdfe89a [rick] update docs
1773d06 [rick] [ZEPPELIN-5445] Allow users to access the spark UI outside the kubernetes cluster

Author: rick

docs/quickstart/kubernetes.md

@@ -245,6 +245,7 @@ to customize,
   4. Run a paragraph will create an interpreter using modified yaml files.
 
 The interpreter pod can also be customized through the interpreter settings. Here are some of the properties:
+
 | Property Name | Default Value | Description |
 | ----- | ----- | ----- |
 | `zeppelin.k8s.namespace` | `default` | The Kubernetes namespace to use. |
@@ -256,6 +257,9 @@ The interpreter pod can also be customized through the interpreter settings. Her
 | `zeppelin.k8s.interpreter.imagePullSecrets` | (optional) | Set the comma-separated list of Kubernetes secrets while pulling images, e.g., `mysecret1,mysecret2` |
 | `zeppelin.k8s.interpreter.container.imagePullPolicy` | (optional) | Set the pull policy of the interpreter image, e.g., `Always` |
 | `zeppelin.k8s.spark.container.imagePullPolicy` | (optional) | Set the pull policy of the spark image, e.g., `Always` |
+| `zeppelin.spark.uiWebUrl` | `//{{PORT}}-{{SERVICE_NAME}}.{{SERVICE_DOMAIN}}` | The URL for user to access Spark UI. The default value is a [jinjava](https://github.com/HubSpot/jinjava) template that contains three variables. |
+| `zeppelin.k8s.spark.useIngress` | (optional) | If true, the [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) will be created when creating the spark interpreter. So users can access the Spark UI through Ingress. |
+| `zeppelin.k8s.spark.ingress.host` | `{{PORT}}-{{SERVICE_NAME}}.{{SERVICE_DOMAIN}}` | If `zeppelin.k8s.spark.useIngress` is `true`, it configures the `host` value of the Ingress. The default value is a [jinjava](https://github.com/HubSpot/jinjava) template that contains three variables. Users can access the Spark UI through a customized `zeppelin.k8s.spark.ingress.host`. |
 
 ## Future work
 

k8s/interpreter/100-interpreter-spec.yaml

@@ -180,4 +180,34 @@ roleRef:
   kind: Role
   name: {{zeppelin.k8s.interpreter.pod.name}}
   apiGroup: rbac.authorization.k8s.io
+{% if zeppelin.k8s.spark.useIngress is defined and zeppelin.k8s.spark.useIngress == "true" %}
+---
+# create ingress of spark UI
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: spark-ui-{{zeppelin.k8s.interpreter.pod.name}}
+  namespace: {{zeppelin.k8s.namespace}}
+  {% if zeppelin.k8s.server.uid is defined %}
+  ownerReferences:
+  - apiVersion: v1
+    controller: false
+    blockOwnerDeletion: false
+    kind: Pod
+    name: {{zeppelin.k8s.server.pod.name}}
+    uid: {{zeppelin.k8s.server.uid}}
+  {% endif %}
+spec:
+  rules:
+  - host: {{zeppelin.k8s.spark.ingress.host}}
+    http:
+      paths:
+      - pathType: Prefix
+        path: "/"
+        backend:
+          service:
+            name: {{zeppelin.k8s.interpreter.pod.name}}
+            port:
+              number: 4040
+{% endif %} 
 {% endif %}

zeppelin-plugins/launcher/k8s-standard/src/main/java/org/apache/zeppelin/interpreter/launcher/K8sRemoteInterpreterProcess.java

@@ -318,6 +318,20 @@ Properties getTemplateBindings(String userName) {
               getPodName(),
               k8sEnv.get(ENV_SERVICE_DOMAIN)
           ));
+
+      // configure interpreter property "zeppelin.k8s.spark.ingress.host" if not defined, to enable spark ui through ingress
+      String ingressHost = (String) properties.get("zeppelin.k8s.spark.ingress.host");
+      if (StringUtils.isBlank(ingressHost)) {
+        ingressHost = "{{PORT}}-{{SERVICE_NAME}}.{{SERVICE_DOMAIN}}";
+      }
+      properties.put("zeppelin.k8s.spark.ingress.host",
+          sparkUiWebUrlFromTemplate(
+              ingressHost,
+              webUiPort,
+              getPodName(),
+              k8sEnv.get(ENV_SERVICE_DOMAIN)
+          ));
+      
       // Resources of Interpreter Pod
       if (properties.containsKey(SPARK_DRIVER_MEMORY)) {
         String memory;