Configure used ActiveJob

[eelcoj]

Last release add process later by default (via active job).

This PR add some improvements + option to define your own job class.

# app/jobs/webhook_processing_job.rb
class WebhookProcessingJob < ApplicationJob
  queue_as :webhooks

  retry_on WebhookError, attempts: 5
  discard_on ActiveJob::DeserializationError

  def perform(event_class_name, webhook_event)
    event_class_name.safe_constantize.new(webhook_event).process!
  end
end

# config/initializers/fuik.rb
Fuik.configure do |config|
  config.webhook_processing_job_class = "WebhookProcessingJob"
end