Suggestion: add "Vector Database" section

[bobvanluijt]

Vector databases are a relatively new phenomenon, but they might deserve their own section.

For the convenience of the maintainer of this repo, I've added two PRs, one without the new section one with the new section.

This reading material about Weaviate might be helpful in the argumentation why the vector database might deserve its own spot on this list :)

• https://db-engines.com/en/blog_post/87
• https://www.zdnet.com/article/weaviate-an-open-source-search-engine-powered-by-machine-learning-vectors-graphs-and-graphql/

[axsaucedo]

This seems interesting but as per CONTRIBUTING.md guidelines 5-10 projects have to be identified, for the time being adding thees to the existing sections is best. Closing but can re-explore if 5-10 can be proposed