Add capability to specify MIME types for MCP tool responses, with special handling for image content.
This enhancement allows tools to return different content types, particularly images, by:
- Adding a new toolResponseMimeType map property to configure response MIME types per tool
- Extending tool registration methods to accept and use MIME type information
- Adding special handling for image content in tool responses
- Updating documentation with the new configuration options
Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>