Desktop integration (#2073)

* Open stash in system tray on Windows/MacOS
* Add desktop notifications
* MacOS Bundling
* Add binary icon

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

vendor/github.com/apenwarr/fixconsole/fixconsole_default.go

@@ -0,0 +1,14 @@
+// +build !windows
+
+package fixconsole
+
+// On non-windows platforms, we don't need to do anything. The console
+// starts off attached already, if it exists.
+
+func AttachConsole() error {
+	return nil
+}
+
+func FixConsoleIfNeeded() error {
+	return nil
+}