Changes:
- Large update of the "internals":
- Upgrade to Laravel 8 and new packages, including the new factories (PHP 7.3 is now required!)
- Icons are now handled by the server, not the browser (#158)
- Usage of new internal templating systems (components)
- Search queries are now escaped properly (#163)
- More options for sorting lists if items (#162)
- Tags are now accessible in the guest view (#160)
- The guest access now has dedicated system settings for dark mode, sharing services,... (#161)
- Fixes issues with the importer (#169)
- Fixes several documentation issues in the README
- Update of translations