Meta - Enabled nullable ref types in Core project

Meta - Simplified R# settings to be more in line with defaults, sorry Darth 😝
Dynamic data models - Implemented add/remove events
Data model paths - Implemented storage

src/Artemis.Storage/Entities/Profile/DataModelPathEntity.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Artemis.Storage.Entities.Profile
+{
+    public class DataModelPathEntity
+    {
+        public string Path { get; set; }
+        public Guid? DataModelGuid { get; set; }
+    }
+}