* Alerting: accept mute_timing_intervals through the api for the embedded alertmanager
* add workaround for mutetimeinterval
* add mute timings to routes
* revert changes
* Update pkg/services/ngalert/api/api_alertmanager.go
* Update pkg/services/ngalert/api/api_alertmanager.go
* Update pkg/services/ngalert/api/api_alertmanager.go
* update prometheus/alertmanager dependency
* add some var docs