Medusa System Added

Read about the medusa system [here](https://nadekobot.readthedocs.io/en/latest/medusa/creating-a-medusa/)

src/NadekoBot/Common/Medusa/MedusaAssemblyLoadContext.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.Loader;
+
+namespace Nadeko.Medusa;
+
+public sealed class MedusaAssemblyLoadContext : AssemblyLoadContext
+{
+    private readonly AssemblyDependencyResolver _depResolver;
+
+    public MedusaAssemblyLoadContext(string pluginPath) : base(isCollectible: true)
+    {
+        _depResolver = new(pluginPath);
+    }
+
+    protected override Assembly? Load(AssemblyName assemblyName)
+    {
+        var assemblyPath = _depResolver.ResolveAssemblyToPath(assemblyName);
+        if (assemblyPath != null)
+        {
+            return LoadFromAssemblyPath(assemblyPath);
+        }
+
+        return null;
+    }
+
+    protected override IntPtr LoadUnmanagedDll(string unmanagedDllName)
+    {
+        var libraryPath = _depResolver.ResolveUnmanagedDllToPath(unmanagedDllName);
+        if (libraryPath != null)
+        {
+            return LoadUnmanagedDllFromPath(libraryPath);
+        }
+
+        return IntPtr.Zero;
+    }
+}