Angular 20 / CoreUI 5 Upgrade

[tobias-weber]

Summary

This PR upgrades the UI from Angular 17 to 20 and CoreUI 4 to 5. Various dependencies have been upgraded as well to ensure compatibility and patch vulnerabilities.

Other Changes

• Upgrade to node version 22
• Fix all build errors and most build warnings
• Streamline theme definitions (we keep CoreUI 4 theme colors)
• Migrate from the deprecated directives (*ngIf) to control flow syntax (@if{...})
• The Left Sidebar no longer uses the c-sidebar component (fixes a lot of problems related to sidebar visibility)
• Remove unused / unsupported packages
• Add patches to ensure compatibility of ng2-charts and plyr package
• Removed the custom webpack builder in preparation for migrating to the new build system

ToDo

• Optional: Migrate to the new ESBuild-based build system (automatic migration results in the build failing for various reasons that are not clear to me)