Issue

Closes langchain4j#2183

Change

Add implementation of EmbeddingStore with DuckDB that supports metadata.
Replace langchain4j/langchain4j#2184

General checklist

• There are no breaking changes
• I have added unit and integration tests for my change
• I have manually run all the unit and integration tests in the module I have added/changed, and they are all green
• I have manually run all the unit and integration tests in the [core](https://github.com/langchain4j/langchain4j/tree/[main](https://github.com/langchain4j/langchain4j/tree/main/langchain4j)/langchain4j-core) and main modules, and they are all green

• I have added/updated the [documentation](https://github.com/langchain4j/langchain4j/tree/main/docs/docs)
• I have added an example in the [examples repo](https://github.com/langchain4j/langchain4j-examples) (only for "big" features)
• I have added/updated [Spring Boot starter(s)](https://github.com/langchain4j/langchain4j-spring) (if applicable)

Checklist for adding new maven module

• I have added my new module in the root pom.xml and langchain4j-bom/pom.xml

Checklist for adding new embedding store integration

• I have added a {NameOfIntegration}EmbeddingStoreIT that extends from either EmbeddingStoreIT or EmbeddingStoreWithFilteringIT
• I have added a {NameOfIntegration}EmbeddingStoreRemovalIT that extends from EmbeddingStoreWithRemovalIT