Splitting Vector Databases into individual cookbooks

[colin-openai]

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This is the first stab at splitting these out individually - there is a common description for all, so it may be worth taking this out and putting it in the README.md instead.

Two still to be finalised:

• Milvus
• Zilliz

Four that do not have a Getting Started notebook but do have a folder:

• AnalyticDB
• Hologres
• Kusto
• SingleStoreDB