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/w32/psapi.go

@@ -0,0 +1,25 @@
+// Copyright 2010-2012 The W32 Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package w32
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var (
+	modpsapi = syscall.NewLazyDLL("psapi.dll")
+
+	procEnumProcesses = modpsapi.NewProc("EnumProcesses")
+)
+
+func EnumProcesses(processIds []uint32, cb uint32, bytesReturned *uint32) bool {
+	ret, _, _ := procEnumProcesses.Call(
+		uintptr(unsafe.Pointer(&processIds[0])),
+		uintptr(cb),
+		uintptr(unsafe.Pointer(bytesReturned)))
+
+	return ret != 0
+}