feat: storage category codegen

[Sanayshah2]

Description of changes

• Added logic to generate code for supported storage category features. Overrides for s3 bucket resource are generated in backend.ts file
• Added a few missing tests for auth external providers.
• Modifications to add overrides as assignments instead of using addPropertyOverride()
• Fix import statements codegen for specific resource

Description of how you validated changes

Unit tests, manual validation, sandbox deployment validation

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies
• Pull request labels are added

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