docs: restructure docs (#14421)

Closes #13434 
Supersedes #14182

---------

Co-authored-by: Ethan <39577870+ethanndickson@users.noreply.github.com>
Co-authored-by: Ethan Dickson <ethan@coder.com>
Co-authored-by: Ben Potter <ben@coder.com>
Co-authored-by: Stephen Kirby <58410745+stirby@users.noreply.github.com>
Co-authored-by: Stephen Kirby <me@skirby.dev>
Co-authored-by: EdwardAngert <17991901+EdwardAngert@users.noreply.github.com>
Co-authored-by: Edward Angert <EdwardAngert@users.noreply.github.com>

docs/tutorials/image-pull-secret.md

@@ -0,0 +1,100 @@
+# Defining ImagePullSecrets for Coder workspaces
+
+<div>
+  <a href="https://github.com/ericpaulsen" style="text-decoration: none; color: inherit;">
+    <span style="vertical-align:middle;">Eric Paulsen</span>
+    <img src="https://github.com/ericpaulsen.png" width="24px" height="24px" style="vertical-align:middle; margin: 0px;"/>
+  </a>
+</div>
+January 12, 2024
+
+---
+
+Coder workspaces are commonly run as Kubernetes pods. When run inside of an
+enterprise, the pod image is typically pulled from a private image registry.
+This guide walks through creating an ImagePullSecret to use for authenticating
+to your registry, and defining it in your workspace template.
+
+## 1. Create Docker Config JSON File
+
+Create a Docker configuration JSON file containing your registry credentials.
+Replace `<your-registry>`, `<your-username>`, and `<your-password>` with your
+actual Docker registry URL, username, and password.
+
+```json
+{
+	"auths": {
+		"<your-registry>": {
+			"username": "<your-username>",
+			"password": "<your-password>"
+		}
+	}
+}
+```
+
+## 2. Create Kubernetes Secret
+
+Run the below `kubectl` command in the K8s cluster where you intend to run your
+Coder workspaces:
+
+```console
+kubectl create secret generic regcred \
+  --from-file=.dockerconfigjson=<path-to-docker-config.json> \
+  --type=kubernetes.io/dockerconfigjson \
+  --namespace=<workspaces-namespace>
+```
+
+Inspect the secret to confirm its contents:
+
+```console
+kubectl get secret -n <workspaces-namespace> regcred --output="jsonpath={.data.\.dockerconfigjson}" | base64 --decode
+```
+
+The output should look similar to this:
+
+```json
+{
+	"auths": {
+		"your.private.registry.com": {
+			"username": "ericpaulsen",
+			"password": "xxxx",
+			"auth": "c3R...zE2"
+		}
+	}
+}
+```
+
+## 3. Define ImagePullSecret in Terraform template
+
+With the ImagePullSecret now created, we can add the secret into the workspace
+template. In the example below, we define the secret via the
+`image_pull_secrets` argument. Note that this argument is nested at the same
+level as the `container` argument:
+
+```tf
+resource "kubernetes_pod" "dev" {
+  metadata {
+    # this must be the same namespace where workspaces will be deployed
+    namespace = "workspaces-namespace"
+  }
+
+  spec {
+    image_pull_secrets {
+      name = "regcred"
+    }
+    container {
+      name  = "dev"
+      image = "your-image:latest"
+    }
+  }
+}
+```
+
+## 4. Push New Template Version
+
+Update your template by running the following commands:
+
+```console
+coder login <access-url>
+coder templates push <template-name>
+```