Medusa System Added

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

src/NadekoBot/Common/Medusa/Adapters/ParamParserAdapter.cs

@@ -0,0 +1,32 @@
+public sealed class ParamParserAdapter<T> : TypeReader
+{
+    private readonly ParamParser<T> _parser;
+    private readonly IMedusaStrings _strings;
+    private readonly IServiceProvider _services;
+
+    public ParamParserAdapter(ParamParser<T> parser,
+        IMedusaStrings strings,
+        IServiceProvider services)
+    {
+        _parser = parser;
+        _strings = strings;
+        _services = services;
+    }
+
+    public override async Task<Discord.Commands.TypeReaderResult> ReadAsync(
+        ICommandContext context,
+        string input,
+        IServiceProvider services)
+    {
+        var medusaContext = ContextAdapterFactory.CreateNew(context,
+            _strings,
+            _services);
+        
+        var result = await _parser.TryParseAsync(medusaContext, input);
+        
+        if(result.IsSuccess)
+            return Discord.Commands.TypeReaderResult.FromSuccess(result.Data);
+        
+        return Discord.Commands.TypeReaderResult.FromError(CommandError.Unsuccessful, "Invalid input");
+    }
+}