ServiceNow task template and notifier

[donaldoakes]

When a manual task is created using ServiceNowTasks.task as its template, MDW will automatically populate fields for the ServiceNow Incident API. The API call will be invoked from a specialized notifier implementation in package com.centurylink.mdw.servicenow.

[donaldoakes]

Outstanding work includes a mechanism to populate fields on the ServiceNow API which can't come directly from TaskInstance. The TaskRuntimeContext has access to all process variables, so we can probably include a mechanism in the yaml template to access variables instead of just task values.