Add file type support for React

[davidchesnut]

Thank you for your pull request! Please provide the following information.

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Change Description:

The template is broken and won't build and run as you will get multiple errors about ttf, woff, and woff2 file types from React usage. This PR updates the webpack.config.js to include these additional file types so they will load correctly.

1. Do these changes impact any npm scripts commands (in package.json)? (e.g., running 'npm run start')
   No.

2. Do these changes impact VS Code debugging options (launch.json)?
   No.

3. Do these changes impact template output? (e.g., add/remove file, update file location, update file contents)
   No.

4. Do these changes impact documentation? (e.g., a tutorial on https://docs.microsoft.com/en-us/office/dev/add-ins/overview/office-add-ins)
   No.

If you answered yes to any of these please do the following:
> Include 'Rick-Kirkham' in the review
> Make sure the README file is correct

Validation/testing performed:

Describe manual testing done.