Migrate bedrock features to langchain-partners

[kzk-maeda]

Checked

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Feature request

I understand that the LangChain package architecture has been divided into core, community, and partner categories. As a result, several major packages, including openai and google-vertexai, have been migrated to the partner category. I believe that the features for Amazon Bedrock should also be migrated to the partner package.

Motivation

If the Bedrock package were included in the partner category, its version could be managed without being affected by other community packages.

Proposal (If applicable)

No response

[eyurtsev]

cc @3coins , @efriis