Add a page detailing a vanilla "Stackable Demo Cluster"

We currently do not give a lot of guidance on how beefy clusters should be that are used to deploy our demos.
One notable exception is the Lakehouse demo that has a disclaimer with a few details.

It can be very frustrating for users to spin up a cluster, deploy the demo and notice that nothing works due to memory limitations or similar things.
Can we maybe come up with one shared cluster definition like 5 nodes, 8 cores, 20 gig ram or something like that, which we describe on an extra page along with proposed instance types on the Hyperscalers, and then we just refer to that page from all demos.

从链接的 Lakehouse 演示页面开始，查看其他演示的文档，以确定当前在哪些位置描述了集群要求。定义一个共享的 Vanilla Stackable Demo Cluster，包含建议的 hyperscaler 实例类型，并从所有演示链接到新页面，以便用户能够以一致的方式确定集群规模。