Release v0.1.3

• There now is a checkbox to allow creating or removing an autostart desktop entry
  (for #6)
  • The autostart entry can now be forced to be created with the external config file /etc/nixbit.conf
  • There also is a new nix module option services.nixbit.forceAutostart for this
• Fix warnings caused by the app icon SVG file (for #2)
• Adapt the window title a bit to show version number at the end
• Wait for network availability after system resume before checking for updates,
  with a 10-second timeout to prevent failures when network is not immediately present
  (for #7)
• A pause/resume button to allow pausing and resuming the running system update
  process was added (for #8)
• Add real-time system resource monitoring (CPU, RAM, network transfer, system load)
  during NixOS updates (for #9)
  • System stats are displayed in a horizontal bar
  • Monitoring automatically starts when an update process begins and stops when it completes
• Some settings were moved to a separate settings dialog to declutter the main window
  (for #9)