Major frontend updates: updated tooling and extracted common configurations and UI components

[raix]

Summary & Motivation

Prepare PlatformPlatform for multiple self-contained systems, ensuring operational consistency between frontends by extracting common configuration and UI components to a new shared-webapp folder next to the shared-kernel used by the backend.

The following changes have been made:

• Switch Yarn to npm - it's "boring" technology but is widely supported both in tooling and organizations
• Move build to Rsbuild, a pre-configured Rsbuild
• Set up Turborepo tooling for working with frontend build dependencies in a mono repository.
• Centralize configurations in shared-webapp repository packages
• Switch Prettier with Biome, allowing for faster cleanup and more flexibility
• Upgrade to React 19 Release Candidate
• Open API json files are now checked in, allowing developers to see changes and build the frontend without first compiling the backend
• Restructure the WebApp with a clear folder structure with /pages, /shared, and /public

Shared WebApp packages:

• config - for TypeScript configurations
• build - Build environment and plugins
• infrastructure - for API / Authentication / Translations / Routing, etc.
• ui - Shared UI components
• utils - for general shared functionality

Finally, this change also removes the need for having the dist folder checked in, and the old client filesystem router has been deleted.

Checklist

• [x] I have added a Label to the pull-request
• [x] I have added tests, and done manual regression tests
• [x] I have updated the documentation, if necessary

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
22.2% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud