PrivateLink availability banner (#4396)

## What are you changing in this pull request and why?

Adds a banner to the PrivateLink pages outlining availability 

## Checklist

- [x] Review the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
and [About
versioning](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#adding-a-new-version)
so my content adheres to these guidelines.
- [x] Add a checklist item for anything that needs to happen before this
PR is merged, such as "needs technical review" or "change base branch."

Adding new pages (delete if not applicable):
- [x] Add page to `website/sidebars.js`
- [x] Provide a unique filename for the new page

website/docs/docs/cloud/secure/about-privatelink.md

@@ -5,6 +5,10 @@ description: "Configuring PrivateLink for AWS"
 sidebar_label: "About PrivateLink"
 ---
 
+import SetUpPages from '/snippets/_available-tiers-privatelink.md';
+
+<SetUpPages features={'/snippets/_available-tiers-privatelink.md'}/>
+
 PrivateLink enables a private connection from any dbt Cloud Multi-Tenant environment to your data platform hosted on AWS using [AWS PrivateLink](https://aws.amazon.com/privatelink/) technology. PrivateLink allows dbt Cloud customers to meet security and compliance controls as it allows connectivity between dbt Cloud and your data platform without traversing the public internet. This feature is supported in most regions across NA, Europe, and Asia, but [contact us](https://www.getdbt.com/contact/) if you have questions about availability. 
 
 ### Cross-region PrivateLink

website/docs/docs/cloud/secure/databricks-privatelink.md

@@ -6,6 +6,10 @@ sidebar_label: "PrivateLink for Databricks"
 pagination_next: null
 ---
 
+import SetUpPages from '/snippets/_available-tiers-privatelink.md';
+
+<SetUpPages features={'/snippets/_available-tiers-privatelink.md'}/>
+
 The following steps will walk you through the setup of a Databricks AWS PrivateLink endpoint in the dbt Cloud multi-tenant environment.
 
 ## Configure PrivateLink

website/docs/docs/cloud/secure/postgres-privatelink.md

@@ -4,6 +4,9 @@ id: postgres-privatelink
 description: "Configuring PrivateLink for Postgres"
 sidebar_label: "PrivateLink for Postgres"
 ---
+import SetUpPages from '/snippets/_available-tiers-privatelink.md';
+
+<SetUpPages features={'/snippets/_available-tiers-privatelink.md'}/>
 
 A Postgres database, hosted either in AWS or in a properly connected on-prem data center, can be accessed through a private network connection using AWS Interface-type PrivateLink. The type of Target Group connected to the Network Load Balancer (NLB) may vary based on the location and type of Postgres instance being connected, as explained in the following steps.
 

website/docs/docs/cloud/secure/redshift-privatelink.md

@@ -5,6 +5,10 @@ description: "Configuring PrivateLink for Redshift"
 sidebar_label: "PrivateLink for Redshift"
 ---
 
+import SetUpPages from '/snippets/_available-tiers-privatelink.md';
+
+<SetUpPages features={'/snippets/_available-tiers-privatelink.md'}/>
+
 AWS provides two different ways to create a PrivateLink VPC endpoint for a Redshift cluster that is running in another VPC: 
 - [Redshift-managed PrivateLink Endpoints](https://docs.aws.amazon.com/redshift/latest/mgmt/managing-cluster-cross-vpc.html)
 - [Redshift Interface-type PrivateLink Endpoints](https://docs.aws.amazon.com/redshift/latest/mgmt/security-private-link.html)

website/docs/docs/cloud/secure/snowflake-privatelink.md

@@ -5,6 +5,10 @@ description: "Configuring PrivateLink for Snowflake"
 sidebar_label: "PrivateLink for Snowflake"
 ---
 
+import SetUpPages from '/snippets/_available-tiers-privatelink.md';
+
+<SetUpPages features={'/snippets/_available-tiers-privatelink.md'}/>
+
 The following steps will walk you through the setup of a Snowflake AWS PrivateLink endpoint in the dbt Cloud multi-tenant environment.
 
 :::note Snowflake SSO with PrivateLink

website/snippets/_available-tiers-privatelink.md

@@ -0,0 +1,9 @@
+:::info Limited to certain Enterprise tiers
+
+The PrivateLink feature is available on the following dbt Cloud Enterprise tiers:
+ * Business Critical 
+ * Virtual Private
+
+To learn more about these tiers, contact us at <sales@getdbt.com>.
+
+:::