Added endpoint to create new summit push notification
POST /api/v1/summits/{id}/notifications
Payload
* channel ( required_if:platform,MOBILE|in:EVERYONE,SPEAKERS,ATTENDEES,MEMBERS,SUMMIT,EVENT,GROUP )
* message ( required|string )
* platform ( required|in:MOBILE,WEB )
* event_id ( required_if:channel,EVENT|integer )
* group_id ( required_if:channel,GROUP|integer )
* recipient_ids ( required_if:channel,MEMBERS|int_array )
Required Scopes
* '%s/summits/write' (OR)
* '%s/summits/write-notifications'
Change-Id: I565407e35d1b73828c52309cadd65b93a7452a7f
c3746d60fb