Add WebhookEvent class and Refator Webhooks

Add a new `WebhookEvent` class to represent Spark generated webhook events.

Apply structural changes to the RoomsAPI and ensure all parameters are up-to-date.

Author: cmlccie

ciscosparkapi/__init__.py

@@ -30,7 +30,7 @@
     TeamMembership,
     TeamMembershipsAPI
 )
-from ciscosparkapi.api.webhooks import Webhook, WebhooksAPI
+from ciscosparkapi.api.webhooks import Webhook, WebhookEvent, WebhooksAPI
 from ciscosparkapi.api.organizations import Organization, OrganizationsAPI
 from ciscosparkapi.api.licenses import License, LicensesAPI
 from ciscosparkapi.api.roles import Role, RolesAPI