Create POC for alternative to separate repo

At a "Sparknotes for .NET" meeting on 1/24/2023, the dev team decided to investigate the use of a separate docs repo to use for creating a book-like documentation experience for ASP.NET Core app types such as gRPC and APIs. This issue is for creating a new independent hub page for content that will reside in a new top-level folder in the existing AspNetCore.Docs repo, as a proof of concept for an alternative approach. This alternative would accomplish the same purpose of creating an independent doc set, but with much less overhead to set up, and it would be easier to share content between the existing doc set and the proposed new doc set.

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[Associated WorkItem - 62253](https://dev.azure.com/msft-skilling/Content/_workitems/edit/62253)