Organize providers exports

[jm42]

Description

This PR organizes the exports of the provider package.

• It exports everything.
• It adds index.ts to export subfolders.
• It moves all types and errors to the ports folder.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update (if none of the other choices apply)

Checklist

• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [ ] I have updated the documentation accordingly.

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