feat(openchallenges): migrate the OC Angular app to Vite (ARCH-337)

[tschaffter]

Closes https://sagebionetworks.jira.com/browse/ARCH-337

Changelog

• Generate a new Angular app project configured to use Vite, update it and then replace the existing app project.
• Specify stylePreprocessorOptions in project.json to reduce the location where the bundle can find styles.
• Remove the sub-folder lib from the project openchallenges-styles and openchallenges-themes.
• Update the paths to styles and themes files after setting stylePreprocessorOptions and refactoring the styles and themes projects.
• Adapt the Dockerfile to the Vite build output.
• Remove custom code previously added to server.ts to inject the server port when using the Express server.
• Remove Tailwind CSS from the project sandbox-angular-app.
• Adapt model-ad-app:build to changes made to the shared styles.

[rrchai]

LGTM and tested!