refactor: Refactor code and show different scripting example

- Refactored code so implementation can be shared between Server and
  DdonGameServer.
- Moved settings into settings module and implemented an example using a
  less structured scripting module interface.
- Created new ScriptableSettings class to assist with interacting with
  non-structured settings module.
- Created README.md files for suggestions and guidelines for module
  implementation.

Arrowgene.Ddon.GameServer/Scripting/ScriptModule.cs

@@ -1,34 +0,0 @@
-using Microsoft.CodeAnalysis.Scripting;
-using System.Collections.Generic;
-using System.IO;
-
-namespace Arrowgene.Ddon.GameServer.Scripting
-{
-    public abstract class ScriptModule
-    {
-        public abstract string ModuleRoot { get; }
-        public abstract string Filter { get; }
-        public abstract bool ScanSubdirectories { get; }
-        public FileSystemWatcher Watcher { get; set; }
-
-        public HashSet<string> Scripts { get; set; }
-
-        public ScriptModule()
-        {
-            Scripts = new HashSet<string>();
-        }
-
-        /// <summary>
-        /// Options passed into the compilation unit.
-        /// </summary>
-        /// <returns></returns>
-        public abstract ScriptOptions Options();
-
-        /// <summary>
-        /// Evaluates the result returned by the script.
-        /// </summary>
-        /// <param name="result"></param>
-        /// <returns></returns>
-        public abstract bool EvaluateResult(ScriptState<object> result);
-    }
-}