Container backport

[nateprewitt]

Description of changes:
This is a temporary backport of #515 to the release prior to the Python pipeline refactoring that's still in progress.

Testing

The simplest way to test is with the awslabs/amazon-ecs-local-container-endpoints container.

Setup environment and Docker

You'll need to set your active credentials in place of test

export AWS_CONTAINER_CREDENTIALS_FULL_URI="http://localhost/creds" 

docker run --rm -it -p 80:80 -e AWS_ACCESS_KEY_ID=test -e AWS_SECRET_ACCESS_KEY=test -e AWS_SESSION_TOKEN=test amazon/amazon-ecs-local-container-endpoints

test.py

import asyncio

from aws_sdk_bedrock_runtime.client import (
    BedrockRuntimeClient,
    ConverseInput,
)
from aws_sdk_bedrock_runtime.models import Message, ContentBlockText
from aws_sdk_bedrock_runtime.config import Config
from aws_sdk_bedrock_runtime.config import HTTPAuthSchemeResolver, SigV4AuthScheme
from smithy_aws_core.credentials_resolvers.container import ContainerCredentialResolver
from smithy_http.aio.crt import AWSCRTHTTPClient

config=Config(
    endpoint_uri="https://bedrock-runtime.us-east-1.amazonaws.com",
    region="us-east-1",
    aws_credentials_identity_resolver=ContainerCredentialResolver(AWSCRTHTTPClient()),
    http_auth_scheme_resolver=HTTPAuthSchemeResolver(),
    http_auth_schemes={
        "aws.auth#sigv4": SigV4AuthScheme(),
    }
)
client = BedrockRuntimeClient(config=config)

async def test():

    messages = [Message(
        role="user",
        content=[ContentBlockText(value="Create a list of 3 best songs from the 1990s")]
    )]

    resp = await client.converse(ConverseInput(model_id='amazon.titan-text-express-v1', messages=messages))
    print(resp)
    
if __name__ == "__main__":
    asyncio.run(test())

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[jonathan343]

I left a couple of comments, but this looks great!

[jonathan343]

Also, we should check if previously fetched credentials aren't expired before fetching new ones

[jonathan343]

LGTM!