Update to .NET 8 and rewrite Developer Excuse to local file instead of API

[omgitsjan]

This pull request includes two significant changes to our application. Firstly, we've updated our project to use the latest .NET 8 framework, bringing improved performance, enhanced features, and better security. Secondly, we've refactored the Developer Excuse feature, transitioning from relying on an external API to using a local file. This shift enhances our application's reliability and reduces external dependencies.

Key Changes

1. Update to .NET 8:

   • The entire project has been upgraded to .NET 8.
   • Necessary adjustments have been made to ensure compatibility with the new framework version.
   • This update paves the way for utilizing the latest .NET features and optimizations.

2. Developer Excuse Refactor:

   • Removed dependency on the external Developer Excuse API.
   • Implemented a local JSON file-based approach for storing and retrieving developer excuses.
   • The feature now reads excuses from excuses.json located in the Data directory, offering quicker access and easier management.
   • Adapted relevant service and tests to align with this new approach.

Benefits

• Upgrading to .NET 8 aligns us with the latest standards and features offered by the .NET ecosystem.
• Local handling of developer excuses improves the feature's speed and reliability as it no longer depends on external API availability.
• This transition also offers more straightforward management and customization of the excuses list.

Testing and Verification

• Extensive testing has been conducted to ensure the application's functionality remains intact post .NET upgrade.
• New unit tests have been added to verify the local file-based Developer Excuse feature, focusing on its ability to handle various scenarios such as empty or invalid JSON files.

This update marks a significant step towards modernizing our application and optimizing its features. Your review and feedback on these changes are highly appreciated.