Support for Bedrock Agents

**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.