Large refactor and project restructuring

PluralKit.Core/Models/PKSwitch.cs

@@ -0,0 +1,17 @@
+using NodaTime;
+
+namespace PluralKit.Core {
+    public class PKSwitch
+    {
+        public int Id { get; set; }
+        public int System { get; set; }
+        public Instant Timestamp { get; set; }
+    }
+    
+    public class PKSwitchMember
+    {
+        public int Id { get; set; }
+        public int Switch { get; set; }
+        public int Member { get; set; }
+    }
+}