chore: add gen2 storage environment

[zchenwei]

Description of changes

Add gen2 storage environment for e2e testing. The backend resource code is stored in the staging repo https://github.com/aws-amplify/amplify-ui-staging/tree/gen2-storage-backend

Note: new permission is required in AmplifyCLIPull policies: "cloudformation:GetTemplateSummary" which I have already updated for the storage e2e test account.

Checklist

• [x] Have read the Pull Request Guidelines
• [x] PR description included
• [x] yarn test passes and tests are updated/added
• [x] No side effects or sideEffects field updated

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[changeset-bot[bot]]

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Latest commit: 548e7315e6e094f541ed61b168d41b0150c46bb8

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[zchenwei]

Closing this one and I will open a new one