feature: hard refresh/empty cache of webkit app via shortcut or menu

# Feature Request
**Specifications:**
- App Version: v3.1.0
- OS (macOS, Windows, Linux): Big Sur 11.5.1

**Description:**
Possibillity to empty the cache of the specific app via CMD+OPTION+E or Menu>"Empty Cache and restart app" In Order to keep the information in the App fresh there has to be a possibility to empty the cache and restart the app for non IT Users.


