docs: Refactor content for new LangGraph Platform deployment options (#4118)

### Summary
This is a large refactor of the content for the LangGraph Platform
deployment options. Although there are a lot of changes, I do feel
fairly confident that this is safe to merge and won't have any negative
impact related to confusion around deployment options. However, please
review thoroughly (i.e. run the docs locally).

### Goals and Non-Goals
Just wanted to explicitly state goals and non-goals so that we're clear
about what needs to be done now versus what can be done in a smaller
follow-up PR.

Goals
1. Add new content for the new deployment options (Self-Hosted Data
Plane, Self-Hosted Control Plane).
1. Hide old content for deprecated deployment options (BYOC).
1. Create a pair of "conceptual" and "how-to" pages for each deployment
option. As much as possible, the pages should have consistent headings.
1. Introduce the terms "control plane" and "data plane" and define them
plainly without hiding/abstracting information.

Non-Goals
1. Do not change the navigation of the existing deployment options. As
much as possible, update content in-place or add new pages. Changing the
navigation is a bigger task that can be done later.
1. Do not remove old content for deprecated deployment options. We may
need to refer to this later. There are only ~2 pages (I think).

### Next Steps
1. Update the architecture diagrams for each deployment option. Commit
Excalidraw file to source control.
1. Create a "how-to" page for the Control Plane UI. This page pertains
to 3/4 deployment options. Most of the content lives in the "how-to"
page for Cloud SaaS deployment.
1. Document required RBAC permissions for K8s for Self-Hosted Data Plane
and Self-Hosted Control Plane (and update links).
1. Figure out how to consolidate plan information.
1. Figure out where to document licensing, telemetry, custom
Postgres/Redis.
1. Update autoscaling content.

docs/docs/cloud/deployment/self_hosted_data_plane.md

@@ -0,0 +1,53 @@
+# How to Deploy Self-Hosted Data Plane
+
+Before deploying, review the [conceptual guide for the Self-Hosted Data Plane](../../concepts/langgraph_self_hosted_data_plane.md) deployment option.
+
+## Prerequisites
+
+1. Use the [LangGraph CLI](../../concepts/langgraph_cli.md) to [test your application locally](./test_locally.md).
+1. Use the [LangGraph CLI](../../concepts/langgraph_cli.md) to build a Docker image (i.e. `langgraph build`) and push it to a registry your Kubernetes cluster or Amazon ECS cluster has access to.
+
+## Kubernetes
+
+### Prerequisites
+1. `KEDA` is installed on your cluster.
+
+        helm repo add kedacore https://kedacore.github.io/charts 
+        helm install keda kedacore/keda --namespace keda --create-namespace
+
+1. A valid `Ingress` controller is install on your cluster.
+1. You have slack space in your cluster for multiple deployments. `Cluster-Autoscaler` is recommended to automatically provision new nodes.
+
+### Setup
+
+1. You give us your LangSmith organization ID. We will enable the Self-Hosted Data Plane for your organization.
+1. We provide you a [Helm chart](https://github.com/langchain-ai/helm/tree/main/charts/langgraph-dataplane) which you run to setup your Kubernetes cluster. This chart contains a few important components.
+    1. `langgraph-listener`: This is a service that listens to LangChain's [control plane](../../concepts/langgraph_control_plane.md) for changes to your deployments and creates/updates downstream CRDs.
+    1. `LangGraphPlatform CRD`: A CRD for LangGraph Platform deployments. This contains the spec for managing an instance of a LangGraph Platform deployment.
+    1. `langgraph-platform-operator`: This operator handles changes to your LangGraph Platform CRDs.
+1. Configure your `langgraph-dataplane-values.yaml` file.
+
+        config:
+          langgraphPlatformLicenseKey: "" # Your LangGraph Platform license key
+          langsmithApiKey: "" # API Key of your Workspace
+          langsmithWorkspaceId: "" # Workspace ID
+          hostBackendUrl: "https://api.host.langchain.com" # Only override this if on EU
+          smithBackendUrl: "https://api.smith.langchain.com" # Only override this if on EU
+
+1. Deploy `langgraph-dataplane` Helm chart.
+
+        helm repo add langchain https://langchain-ai.github.io/helm/
+        helm repo update
+        helm upgrade -i langgraph-dataplane langchain/langgraph-dataplane --values langgraph-dataplane-values.yaml
+
+1. If successful, you will see two services start up in your namespace.
+
+        NAME                                          READY   STATUS              RESTARTS   AGE
+        langgraph-dataplane-listener-7fccd788-wn2dx   0/1     Running             0          9s
+        langgraph-dataplane-redis-0                   0/1     ContainerCreating   0          9s
+
+1. You create a deployment from the [Control Plane UI](../../concepts/langgraph_control_plane.md#control-plane-ui).
+
+## Amazon ECS
+
+Coming soon!