feat: Added Elasticsearch database.

[HavenDV]

Docs: https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/getting-started-net.html#_creating_an_index

Summary by CodeRabbit

• New Features

  • Introduced support for Elasticsearch, including the addition of ElasticsearchVectorCollection and ElasticsearchVectorDatabase classes.
  • Added methods for creating, retrieving, deleting, and searching vector collections in Elasticsearch.
  • Integration of Elasticsearch in various database test cases and configurations.

• Tests

  • Expanded tests to include Elasticsearch, ensuring compatibility and performance for various database operations.

• Chores

  • Added necessary package references and project configurations to support Elasticsearch integration.