sprint-13-release-candidate

Includes:

• [FE] Redesigned user interface
• [FE] New dialog if user session expires
• [BE] Faster execution of AI models via multithreading
• [EP] Stabilized email proxy ignoring emails from Microsoft
• [AI] Better title and keyword predictions
• [AI] Adapted category values
• [BE] Increased code coverage of the tests (~90%)
• Updated documentation