Add auto updater configuration (#122)

Adds a new set of configurations for managing whether the app will
automatically check for updates. Ports over the auto update code from
the old app. In this version, the main difference is that updates can be
manually checked for using a menu bar item, even if auto updates are
disabled.

pkg/service/fileservice/fileservice.go

@@ -161,7 +161,7 @@ func (fs *FileService) DeleteFile(path string) error {
 	return os.Remove(cleanedPath)
 }
 
-func (fs *FileService) GetSettingsConfig() interface{} {
+func (fs *FileService) GetSettingsConfig() wconfig.SettingsConfigType {
 	watcher := wconfig.GetWatcher()
 	return watcher.GetSettingsConfig()
 }