feat: Splits Server in Core and Application (#1806)

> [!Note]
> **Developer Note**
> Now developers will only need to build/run the Application project instead of everything.
> When adding new projects, make sure to: 
> 1. Add a reference to that project in the Application project.
> 2. Add the dll file to the Distribution/Data/assemblies.json file

### Summary
- Adds an application project
- Consolidates process restarts to use `Core.Kill(true)`
- Removes some old messaging, for example processor optimization
- Fixes missing build cleanup

Projects/UOContent.Tests/Tests/Engines/Help/HelpTopic.cs

@@ -1,9 +1,9 @@
-namespace Server.Network
+namespace Server.Network;
+
+public class DisplayHelpTopic : Packet
 {
-    public class DisplayHelpTopic : Packet
+    public DisplayHelpTopic(int topicID, bool display) : base(0xBF)
     {
-        public DisplayHelpTopic(int topicID, bool display) : base(0xBF)
-        {
             EnsureCapacity(11);
 
             Stream.Write((short)0x17);
@@ -11,5 +11,4 @@ namespace Server.Network
             Stream.Write(topicID);
             Stream.Write(display);
         }
-    }
-}
+}