Dynamic space world generation and debris. (#15120)

* World generation (squash)

* Test fixes.

* command

* o

* Access cleanup.

* Documentation touchups.

* Use a prototype serializer for BiomeSelectionComponent

* Struct enumerator in SimpleFloorPlanPopulatorSystem

* Safety margins around PoissonDiskSampler, cookie acquisition methodologies

* Struct enumerating PoissonDiskSampler; internal side

* Struct enumerating PoissonDiskSampler: Finish it

* Update WorldgenConfigSystem.cs

awa

---------

Co-authored-by: moonheart08 <moonheart08@users.noreply.github.com>
Co-authored-by: 20kdc <asdd2808@gmail.com>

Content.Server/Worldgen/GridPointsNearEnumerator.cs

@@ -0,0 +1,59 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+
+namespace Content.Server.Worldgen;
+
+/// <summary>
+///     A struct enumerator of points on a grid within the given radius.
+/// </summary>
+public struct GridPointsNearEnumerator
+{
+    private readonly int _radius;
+    private readonly Vector2i _center;
+    private int _x;
+    private int _y;
+
+    /// <summary>
+    ///     Initializes a new enumerator with the given center and radius.
+    /// </summary>
+    public GridPointsNearEnumerator(Vector2i center, int radius)
+    {
+        _radius = radius;
+        _center = center;
+        _x = -_radius;
+        _y = -_radius;
+    }
+
+    /// <summary>
+    ///     Gets the next point in the enumeration.
+    /// </summary>
+    /// <param name="chunk">The computed point, if any</param>
+    /// <returns>Success</returns>
+    [Pure]
+    public bool MoveNext([NotNullWhen(true)] out Vector2i? chunk)
+    {
+        while (!(_x * _x + _y * _y <= _radius * _radius))
+        {
+            if (_y > _radius)
+            {
+                chunk = null;
+                return false;
+            }
+
+            if (_x > _radius)
+            {
+                _x = -_radius;
+                _y++;
+            }
+            else
+            {
+                _x++;
+            }
+        }
+
+        chunk = _center + new Vector2i(_x, _y);
+        _x++;
+        return true;
+    }
+}
+