Some mobs pvs-based systems (#321)

* outPVS despawn component

* Update CP14HelperPvsSystem.cs

* experimental constrained spawners

Content.Server/_CP14/PVS/CP14HelperPvsSystem.cs

@@ -0,0 +1,63 @@
+using Content.Server.Administration.Logs;
+using Content.Shared.Database;
+using Content.Shared.Ghost;
+using Content.Shared.Mind.Components;
+using Robust.Shared;
+using Robust.Shared.Timing;
+
+namespace Content.Server._CP14.PVS;
+
+public sealed partial class CP14HelperPvsSystem : EntitySystem
+{
+    [Dependency] private readonly IGameTiming _timing = default!;
+    [Dependency] private readonly EntityLookupSystem _lookup = default!;
+    [Dependency] private readonly IAdminLogManager _adminLogger = default!;
+
+    private static readonly TimeSpan UpdateFrequency = TimeSpan.FromSeconds(5f);
+
+    public override void Update(float frameTime)
+    {
+        base.Update(frameTime);
+
+        var query = EntityQueryEnumerator<CP14OutPVSDespawnComponent>();
+        while (query.MoveNext(out var uid, out var pvs))
+        {
+            if (_timing.CurTime <= pvs.NextUpdate)
+                continue;
+
+            pvs.NextUpdate = _timing.CurTime + UpdateFrequency;
+
+            if (InPvs(uid))
+            {
+                pvs.DespawnAttempt = pvs.MaxDespawnAttempt;
+            }
+            else
+            {
+                pvs.DespawnAttempt--;
+            }
+
+            if (pvs.DespawnAttempt <= 0)
+            {
+                _adminLogger.Add(LogType.EntityDelete, LogImpact.Medium, $"{ToPrettyString(uid):entity} was out of the players' pvs for too long and was deleted");
+                QueueDel(uid);
+            }
+        }
+    }
+
+    public bool InPvs(EntityUid uid)
+    {
+        var nearMinds = _lookup.GetEntitiesInRange<MindContainerComponent>(Transform(uid).Coordinates, CVars.NetMaxUpdateRange.DefaultValue / 2);
+        foreach (var mind in nearMinds)
+        {
+            if (HasComp<GhostComponent>(mind))
+                continue;
+
+            if (!mind.Comp.HasMind)
+                continue;
+
+            return true;
+        }
+
+        return false;
+    }
+}