Support for Bedrock Agents

[veeragoni]

The current issue:

• Bedrock Agents' POST requests are not returning properly formatted JSON.
• Customers using REST-based web tools don't want to process data chunks.

Proposed solution:

• Use boto3 to interact with Bedrock Agents, as it's more reliable via this gateway
• Create REST abstractions to simplify the process for customers.

This approach would improve data formatting and reduce the need for additional processing on the client side.