i18n (#77)

* - initialize localization with English
- add i18n to app settings

* - add translation to widget settings

* - add translation to CPU

* - add translation to GPU

* - add translation to Memory

* - add translation to Disk

* - add translation to Sensors
- add translation to Network

* - add translation to Battery

* - add Polish language
- small fixes in translation

* - add Ukrainian language

Modules/Sensors/settings.swift

@@ -66,7 +66,7 @@ internal class Settings: NSView, Settings_v {
         
         self.addSubview(SelectTitleRow(
             frame: NSRect(x: Constants.Settings.margin, y: height - rowHeight, width: view.frame.width, height: rowHeight),
-            title: "Update interval",
+            title: LocalizedString("Update interval"),
             action: #selector(changeUpdateInterval),
             items: self.listOfUpdateIntervals.map{ "\($0) sec" },
             selected: "\(self.updateIntervalValue) sec"