Support AWS China

[maxsxu]

Fixes #68

Motivation

Support AWS China.

Modifications

• Add partition in IAM bootstrap to make was partition configurable
• Add a new IAM role binding StreamNativeCloudManagementRole trusted user/aws-cn-test. As AWS China have to use the generic authentication approach
• Add sts.amazonaws.com to openid_connect_audiences. As applications like external-dns cannot utilize the generated sts.amazonaws.com.cn
• Add aws-cn in validation rule at modules/vpc/variables.tf
• Make aws partition configurable by reusing the var.aws_partition

Verifying this change

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This change is a trivial rework / code cleanup without any test coverage.

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This change is already covered by existing tests, such as (please describe tests).

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This change added tests and can be verified as follows:

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• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Documentation

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[github-actions]

@maxsxu:Thanks for your contribution. For this PR, do we need to update docs?
(The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[jrsdav]

This looks good to me, just note that PR #72 brought in some changes to the managed-cloud module, in particular a new set of *-runtime.json.tpl files that will need the var.partition interpolation.

[jrsdav]

Looks great, very thorough. Thanks @maxsxu!