ST: Allow Slack Notification Payload Customization

The Slack notifications from Staircase are cool, and fairly easy to set up. It would be great though, if we had the ability to customize the payload.

You could get around this by using webhooks, which would be fine for advanced set up and more complex needs, but the OOB notifications to Slack would benefit from the simple ability to toggle which fields you wanted to see.

This would allow some customization, without a lot of additional overhead to build, configure, and maintain webhooks that are essentially duplicating the OOB setup for some minor changes.