Adds the option to fit the viewport to vertical screenspace (#27061)

* Adds the option to fit your viewport to your vertical screenspace

* fixes documentation

* Removes commented-out leftover

* Hides the viewport width slider and also we dont know if the viewport width causing stretching/squishing was a bug present before but we fixed that while we were at it

* Removes commented out leftovers

Content.Shared/CCVar/CCVars.cs

@@ -1555,6 +1555,9 @@ namespace Content.Shared.CCVar
         public static readonly CVarDef<int> ViewportWidth =
             CVarDef.Create("viewport.width", 21, CVar.CLIENTONLY | CVar.ARCHIVE);
 
+        public static readonly CVarDef<bool> ViewportVerticalFit =
+            CVarDef.Create("viewport.vertical_fit", true, CVar.CLIENTONLY | CVar.ARCHIVE);
+
         /*
          * UI
          */