Create a JSON schema for generic webhooks

Created by: limitedmage

This is the schema for the JSON that is sent when calling generic webhooks.

It probably should contain:

• Name of the monitor
• Link to the monitor
• Type of trigger (We currently only have one trigger, new search results, but more triggers may come eventually)
• Details from the trigger (For new search results, the details could be the number of search results and the link to the search results.)

@limitedmage putting our Code monitor payload doc here just for reference. Let me know if more discussion is required, the doc isn't finalized so we may need to revive the conversation. cc @camdencheek.