[FEATURE] Add AWS Bedrock LLM Support

[djakish]

What is the use case?
The ability to use the Bedrock for LLM parsing.
Describe the solution you'd like
Something like this

cocoindex.LlmSpec(
    api_type=cocoindex.LlmApiType.BEDROCK,
    model="us.anthropic.claude-3-5-haiku-20241022-v1:0",
)

Additional context
Bedrock now has API keys, maybe it can work like Anthropic code does.
https://aws.amazon.com/blogs/machine-learning/accelerate-ai-development-with-amazon-bedrock-api-keys
From the article:

curl -X POST "https://bedrock-runtime.us-east-1.amazonaws.com/model/us.anthropic.claude-3-5-haiku-20241022-v1:0/converse" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $AWS_BEARER_TOKEN_BEDROCK" \
  -d '{
    "messages": [
        {
            "role": "user",
            "content": [{"text": "Hello"}]
        }
    ]
  }'

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[belloibrahv]

Can I work on this issue? Please assign to me.

[georgeh0]

Assigned the issue. Thanks for contributing!