Use Vite for display test app

[kckst8]

Replace usage of react-scripts in display-test-app with Vite. Read the README.md file within the app for instructions on how to run and build for web and/or desktop (electron). Ensure that all works with Vite. The frontend should use Vite, but the backend scripts can remain as is and they are setup to use commonjs modules. You can use the vite.config.ts file from iTwin Studio as a starting point. Can also use the Studio app for guidance in general, but keep in mind it is electron only.

[pmconne]

Please update description to indicate the motivation behind and ramifications of this change. Or, fill out the provided enhancement issue template.

[aruniverse]

closed by https://github.com/iTwin/itwinjs-core/pull/5605