[New article]: Community Toolkit docs for vector DB providers/connectors

### Proposed topic or title

Community Toolkit docs for vector DB providers/connectors

### Location in table of contents

/docs/ai/vector-stores

### Repo for docs

https://github.com/MicrosoftDocs/CommunityToolkit

### Reason for the article

The [community toolkit](https://github.com/CommunityToolkit/AI) is a place for tools that customers can use for .NET development that aren't part of the officially shipping packages. The Semantic Kernel connectors were renamed and updated for Microsoft.Extensions and moved to the [community toolkit repo](https://github.com/CommunityToolkit/AI/tree/main/MEVD/src). We should document these (and other community toolkit tools).

From Luis: Prioritize Microsoft-owned connectors, i.e. Azure, CosmosDB, SqlServer.

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[Associated WorkItem - 558644](https://dev.azure.com/msft-skilling/Content/_workitems/edit/558644)