feat: Update AWS KB retrieval server with improved credential handling

[zxkane]

The commit message captures the key changes made to the AWS Knowledge Base retrieval server:

1. Enhanced credential handling by supporting multiple authentication methods:

   • Explicit AWS access key and secret key
   • AWS profile credentials
   • AWS provider chain (e.g., EC2 IAM roles)

2. Added more robust error logging for credential loading

3. Configured longer timeouts for network requests

4. Updated dependencies to support new credential providers

The changes improve the flexibility and reliability of AWS credential management in the server.

Description

Server Details

• Server:
• Changes to: AWS Knowledge Base

Motivation and Context

How Has This Been Tested?

Breaking Changes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context