Adds a domain to a watchlist in Cisco Secure Cloud Analytics.

Target: Secure Cloud Analytics - v3 integration target or an HTTP Endpoint for "<your tenant>.obsrvbl.com" with a path of "/api"

Account Key: None if using an integration-provided target, API key if using an HTTP Endpoint target

Steps:
[] Validate the API path
[] Build the authorization header
[] Build the JSON payload to POST
[] Request the domain be added to the watchlist
[] Check if the request was successful:
[]> If it was, extract the entry ID and set the output variable
[]> If it wasn't, return an error

More information about this API: https://developer.cisco.com/docs/stealthwatch/cloud/#!stealthwatch-cloud-api-version-3

Cisco Secure Cloud Analytics - Add Domain to Watchlist