1.6.0

- ✨ Adjust design to new style of Nextcloud Android app (#525)
- 🎨 Brand now uses board color to provide better context (#525)
- 🎨 Offer the same default board colors as the server app
- 🔍 Display all available users as search results when sharing a board (#510)
- 🐞 "Archive cards" of list crashes the app when there is no list (#557)