[CALCITE-7353] introduce Milvus adapter with scan and convention support

[wg1026688210]

Add the foundational Milvus adapter module to Apache Calcite:

• MilvusRel convention interface and MilvusTableScan operator
• MilvusSchema / MilvusSchemaFactory for schema integration
• MilvusTranslatableTable with scan() for collection reads
• MilvusToEnumerableConverter and converter rule for code generation
• MilvusQueryEnumerator with pagination via MilvusRowIterator
• MilvusProjectExpression for projection handling
• Test infrastructure: E2E base, JUnit 5 extension, Testcontainers

This is the minimal skeleton; Filter/Project/VectorSearch rules are intentionally omitted for subsequent PRs.

[cjj2010]

CI error:
"Caused by: java.lang.IllegalStateException: Could not find a valid Docker environment. Please see logs and check configuration"
It seems to be related to the Docker environment. Alternatively, you can check how the Redis adapter builds the Docker environment