KTailctl v0.17.0

This update refactors most of the backend of the app and improves the performance of the main window as well as the tray menu.
It also adds a new dedicated page for managing exit nodes as wel as new colorful tray icons.

New Features

• Add dedicated exit node page
• Display suggested exit node (tray menu & exit node page)
• Do not show trailing dot in DNS names
• Add new color schemes for the tray icon
• Default refresh rate is now 1s (balance between recency and efficiency)
• Preloading of pages for the main window to enable much quicker navigation at cost of slower startup
• Refactoring of tray menu to load much quicker by only rebuilding changed components

Bugfixes

• Fix alignment in chip delegates for FormCard
• Fix logo on about page
• Show country flag for mullvad nodes in tray menu

Chores

• Create a devenv for easy development using nix
• Update tailscale.com to v1.68.2
• Update kirigami-addons to v1.3.0
• Update golang.org/x/net to v0.27.0
• Fix some clang-tidy warnings
• Refactor exit node helpers
• Add CMake library aliases
• Remove AppImage build for now
• Completely refactored backend code around Tailscale status:
  • Now centered around a PeerModel
  • Exit nodes accessible via proxy models
  • Add default empty location info to all nodes
• Use .hpp extension for C++ headers
• Programatically generate tray icons for different color schemes