chore: renaming references of StorageManager within react-storage

[jordanvn]

Description of changes

• Rename Storage Manager to File Uploader
  • File names are not changed yet, for clearer review
  • Only files within the react-storage package are touched, with the exception of adding FileUploader to component class names
• Storage Manager is maintained as an alias in all exported values
• Internal usage of Storage Manager within package is converted to File Uploader

Note: other updates will follow for themes, example apps, docs, and file names

Issue #, if available

Description of how you validated changes

Checklist

• [x] Have read the Pull Request Guidelines
• [x] PR description included
• [x] yarn test passes and tests are updated/added
• [x] PR title and commit messages follow conventional commit syntax
• [ ] If this change should result in a version bump, changeset added (This can be done after creating the PR.) This does not apply to changes made to docs, e2e, examples, or other private packages.

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