Right now configured headers are only set on requests made from the backend to alertmanager API.
With this change fetch() calls in the browser will use those headers if proxy mode is not enabled.
If all alerts in a group are silenced and the same silence ID is used for all of them then there's no point in rendering silence object for each of the alerts, since they are all identical. Move the silence rendering to the footer if that happens so we save screen space
Right now we don't mark inhibted alerts in any way, so they look like silenced alerts with no silence details. Add an icon with tooltip so inhibited alerts can be easily distinguished from silenced onces
