* accounts overview: show sync/refresh status of every account with a progress bar
* accounts overview: new *Sync all accounts* action
* launcher shortcut: *Sync all accounts* (available as DAVx⁵ has been started the first time); can be used as widget
* new debug info/share logs screen
  * improved UI (including specific messages for common errors)
  * improved debug info (more information, better readability)
  * *Share* action now generates a ZIP file with debug info (and logs, if available)

