show non-sheet material units in lathe (#19896)

* locale for material units

* use material units in lathe ui

* give units to non-sheet materials

* :trollface:

* use volume properly

* :trollface:

* review

---------

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Shared/Materials/MaterialPrototype.cs

@@ -33,7 +33,15 @@ namespace Content.Shared.Materials
         public string? StackEntity;
 
         [DataField("name")]
-        public string Name = "";
+        public string Name = string.Empty;
+
+        /// <summary>
+        /// Locale id for the unit of this material.
+        /// Lathe recipe tooltips and material storage display use this to let you change a material to sound nicer.
+        /// For example, 5 bars of gold is better than 5 sheets of gold.
+        /// </summary>
+        [DataField("unit")]
+        public string Unit = "materials-unit-sheet";
 
         [DataField("color")]
         public Color Color { get; private set; } = Color.Gray;