Puddles & spreader refactor (#15191)

Content.Server/Spreader/KudzuComponent.cs

@@ -0,0 +1,14 @@
+namespace Content.Server.Spreader;
+
+/// <summary>
+/// Handles entities that spread out when they reach the relevant growth level.
+/// </summary>
+[RegisterComponent]
+public sealed class KudzuComponent : Component
+{
+    /// <summary>
+    /// Chance to spread whenever an edge spread is possible.
+    /// </summary>
+    [DataField("spreadChance")]
+    public float SpreadChance = 1f;
+}