feat: add webhooks

[null8626]

The following pull request is a toned down version of #29. This pull request focuses solely on adding a webhooks wrapper for ASP.NET Core/Blazor.

[velddev]

This is not how a ASP.NET Core webhook endpoint should look like. Prefer using the minimal API to create a route at build-time. This will let the internal ASP.NET core router handle all of the actual context.

public static class RoutingExtension {
  public static void UseVoteWebhook(IRouteEndpointBuilder router, string path, ...) {
    router.MapGet(path, (req) => {
      ...
    });  
  }
}

[null8626]

Will work on it.

[null8626]

Done. Made it more similar to Node.js SDK' webhooks wrapper.

Example usage:

using DiscordBotsList.Api.Webhooks;

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello World!");

var webhooks = new Webhooks("my webhook secret");

app.MapPost("/webhooks", webhooks.Listener((context, vote) =>
{
    Console.WriteLine($"A user with the ID of {vote.VoterId} has voted us on Top.gg!");

    return Task.CompletedTask;
}));

app.Run();