Updates to the Azure Service Health API endpoint

**Request: Introducing new fields to the response payload.**

1. It would be very useful to be able to differentiate an Azure Service Event by its active event type: Service Health, Planned Maintenance, Security Advisory, Health Advisory. This allows our customers to easily recognize the type of service health event, as it aligns with the literature used within Azure.


2. Adding an end-event-timestamp for Planned Maintenances. This information is usually in the description and would be a suited candidate for its own field.


3. Adding the redirect URL to the event in the response payload. This would allow us to quickly send our customers back to the Service health portal if they need more information about an incident's progression.


We are currently using this API endpoint:

https://management.azure.com/subscriptions/00000000-0000-0000-0000-000000000000/providers/microsoft.insights/eventtypes/management/values?api-version=2017-03-01-preview&%24filter=eventTimestamp+ge+%272019-01-25T15%3a06%3a02Z%27+and+eventTimestamp+le+%272019-01-25T21%3a09%3a02Z%27+and+categories+eq+%27ServiceHealth%27

Start with the Azure Service Health API endpoint and its 2017-03-01-preview version, then locate the corresponding REST API specification in this repository. Check how the response currently represents event type, planned-maintenance end time, and the redirect URL; done means the specification exposes all three requested fields with agreed names and types.

Written by the indexing model from the issue text.