refactor: rearrange and add solution for 4-series

src/PepperDash.Essentials.Core/Occupancy/OccupancyAggregatorConfig.cs

@@ -0,0 +1,17 @@
+extern alias Full;
+
+using System.Collections.Generic;
+using Full.Newtonsoft.Json;
+
+namespace PepperDash.Essentials.Core
+{
+    public class OccupancyAggregatorConfig
+    {
+        [JsonProperty("deviceKeys")] public List<string> DeviceKeys { get; set; }
+
+        public OccupancyAggregatorConfig()
+        {
+            DeviceKeys = new List<string>();
+        }
+    }
+}