Entity Tables (EntitySpawnEntry replacement) (#30579)

* Entity table code

* entity table examples

* fix dat shit

* access

* tests tests tests

* sloth review

Content.Shared/EntityTable/EntitySelectors/GroupSelector.cs

@@ -0,0 +1,28 @@
+using Content.Shared.Random.Helpers;
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.EntityTable.EntitySelectors;
+
+/// <summary>
+/// Gets the spawns from one of the child selectors, based on the weight of the children
+/// </summary>
+public sealed partial class GroupSelector : EntityTableSelector
+{
+    [DataField(required: true)]
+    public List<EntityTableSelector> Children = new();
+
+    protected override IEnumerable<EntProtoId> GetSpawnsImplementation(System.Random rand,
+        IEntityManager entMan,
+        IPrototypeManager proto)
+    {
+        var children = new Dictionary<EntityTableSelector, float>(Children.Count);
+        foreach (var child in Children)
+        {
+            children.Add(child, child.Weight);
+        }
+
+        var pick = SharedRandomExtensions.Pick(children, rand);
+
+        return pick.GetSpawns(rand, entMan, proto);
+    }
+}