Refactor Advisor Interfaces and add AroundAdvisor support

[tzolov]

Refactoring and enhancements to the advisor functionality.

 New Advisor interfaces in the org.springframework.ai.chat.client.advisor.api package:
 - Advisor: Base interface for all advisor types.
 - RequestAdvisor: For advising on request data before execution.
 - ResponseAdvisor: For advising on response data after execution, with enhanced streaming modes.
 - CallAroundAdvisor and StreamAroundAdvisor: For around advice on synchronous and streaming requests respectively.
 - AroundAdvisorChain and DefaultAroundAdvisorChain: To manage chaining of around advisors.

 Advisor Chain and Prompt Generation:
 - Added the DefaultAroundAdvisorChain class to manage the sequence of advisors applied around chat model methods.
 - Adjusted the prompt generation (toPrompt) to integrate with the refactored AdvisedRequest object.

 Refactoring and Updates:
 - Replaced the deprecated RequestResponseAdvisor interface with RequestAdvisor and ResponseAdvisor across the spring-ai-core and test modules.
 - Updated the DefaultChatClient and related classes to use the new Advisor interface, improving modularity and consistency.
 - Refactored DefaultAdvisorSpec and DefaultChatClientRequestSpec to handle the new Advisor type, and revised advisor lists and methods accordingly.
 - Enhanced the handling of streaming responses, introducing StreamResponseMode for better control during streaming scenarios.

[tzolov]

Merged at 28276d1