Now that Alertmanager provides status=(unprocessed|suppressed|active) in the API it doesn't make sense to keep having separate filters for each value, merge @silenced & @inhibited into a single filter, update docs and UI
There's a bogus duplicated mouse event for a.silence-duration-btn, which I added to fix css issues, get rid of it and replace with proper css selectors. And with that drop the event.stopPropagation call as it shouldn't be needed anymore
Instead of showing start & end inputs show duration input element, explicit start & end are still present under tabs, where datatime picker is inlined (so it doesn't require any click to show controls). Tabs will also show desription of relative start and end, so it should be more readable what is the real duration of a silence
This commit turns label checkboxes into multiselect dropdowns that are populated from all labels of all instances of current alert (matched by alertname label). There is also a cocollapsible preview box that allows user to inspect raw silence JSON object we will send to the Alertmanager API. Fixes#69
