Spring-ai Add NOT operator to VectorStore portable filter expressions

• Add NOT expression type to the portable Filter.Expression model.
• Add NOT to the Antlr grammar and implement the related parser listener method to generate Filter NOT expressions.
• Add NOT support to the filter programming DSL.
• Implement FilterHelper.negation for logically transform any boolean expression with NOT statements into semantically equivalent one with NOT applied to the leaf expressions.
• Add tests for paresers, converters and vectorsores ITs.

Comment From: tzolov

replaced by https://github.com/spring-projects/spring-ai/pull/128