doc: Added kubectl port-fwd section in RB (#5139)

* Added kubectl port-fwd section in RB

* Proofreading completed

* Incorporated PM Feedback + Added Session Token Method

* Completed Second Proofreading

* URL Format + Indentation Fix + Added Table for Placeholders

Author: ashokdevtron

docs/user-guide/resource-browser.md

@@ -449,3 +449,78 @@ spec:
          - containerPort: 80
 ```
 {% endcode %}
+
+---
+
+## Port Forwarding
+
+### Introduction
+
+Assume your applications are running in a Kubernetes cluster on cloud. Now, if you wish to test or debug them on your local machine, you can perform [port forwarding](https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/). It creates a tunnel between a port on your machine and a port on a resource within your cluster. Therefore, you can access applications running inside the cluster as though they are running locally on your machine.
+
+But first, you would need access to that cluster. Traditionally, the kubeconfig file (`./kube/config`) helps you connect with the cluster. 
+
+![Figure 21: Kubeconfig File](https://devtron-public-asset.s3.us-east-2.amazonaws.com/images/kubernetes-resource-browser/kubeconfig.jpg)
+
+### Challenges in Kubeconfig
+
+Kubeconfig becomes painstakingly difficult to maintain especially when it comes to:
+* Granting or revoking access to the cluster for multiple people
+* Changing the permissions and subsequently the access token
+* Adding/Updating/Deleting the entries of cluster URLs and tokens
+* Keeping a record of multiple kubeconfig files
+
+### Our Solution
+
+Devtron helps in reducing the challenges and simplifying the maintenance of kubeconfig file through:
+* **Devtron's Proxy URL for Cluster** - A standardized URL that you can use in place of your Kubernetes cluster URL.
+* **Devtron's Access Token** - A kubectl-compatible token which can be generated and centrally maintained from [Global Configurations → Authorization → API tokens](./global-configurations/authorization/api-tokens.md).
+
+### Steps
+
+**Prerequisite**: An [API token with necessary permissions](./global-configurations/authorization/api-tokens.md) for the user(s) to access the cluster. 
+
+If you are not a super-admin and can't generate a token yourself, you can find the session token (argocd.token) using the Developer Tools available in your web browser as shown below.
+
+![Figure 22: Using Session Token](https://devtron-public-asset.s3.us-east-2.amazonaws.com/images/kubernetes-resource-browser/argocd-token-v1.gif)
+
+1. Go to `~/.kube` folder on your local machine and open the `config` file. Or you may create one with the following content:
+
+  {% code title="kubeconfig" overflow="wrap" lineNumbers="true" %}
+  ```yaml
+  apiVersion: v1
+  kind: Config
+  clusters:
+  - cluster:
+      insecure-skip-tls-verify: true
+      server: https://<devtron_host_name>/orchestrator/k8s/proxy/cluster/<cluster_name>
+    name: devtron-cluster
+  contexts:
+  - context:
+      cluster: devtron-cluster
+      user: admin
+    name: devtron-cluster
+  current-context: devtron-cluster
+  users:
+  - name: admin
+    user:
+      token: <devtron_token>
+  ```
+  {% endcode %}
+
+2. Edit the following placeholders in the `server` field and the `token` field:
+
+  | Placeholder         | Description                         | Example                                         |
+  | ------------------- | ----------------------------------- | ----------------------------------------------- |
+  | <devtron_host_name> | Hostname of the Devtron server      | demo.devtron.ai                                 |
+  | <cluster_name>      | Name of the cluster (or cluster ID) | devtron-cluster                                 |
+  | <devtron_token>     | API token or session token          | \-                                              |
+
+  ![Figure 23: Editing Kubeconfig File](https://devtron-public-asset.s3.us-east-2.amazonaws.com/images/kubernetes-resource-browser/kubeconfig.gif)
+
+3. Test the connection to the cluster by running any kubectl command, e.g., `kubectl get ns` or `kubectl get po -A`
+
+4. Once you have successfully connected to the cluster, you may run the port-forward command. Refer [kubectl port-forward](https://kubernetes.io/docs/reference/kubectl/generated/kubectl_port-forward/) to see a few examples.
+
+  ![Figure 24: Example - Port Forwarding](https://devtron-public-asset.s3.us-east-2.amazonaws.com/images/kubernetes-resource-browser/port-forward.gif)
+