Typo, redundant string interpolation, namespaces and imports cleanup (#2068)

* Readonly, typos and redundant string interpolations

* Namespaces

* Optimize imports

* Address reviews

* but actually

* Localize missing strings

* Remove redundant vars

Content.Client/GameObjects/Components/Body/Scanner/BodyScannerDisplay.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.Globalization;
 using Content.Shared.Body.Scanner;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.CustomControls;