UI: Option to hide inhibited alerts

[beorn7]

Similar to silenced alerts, there should be an option to hide inhibited alerts.
After a short discussion with @w0rm , we concluded that it's most likely the same situation, i.e. we don't need to bloat the UI with two separate checkboxes, but rather have a checkbox Show Silenced/Inhibited rather than the current Show Silenced. We can do this as a first attempt and see if it is sufficient. If people then have legitimate need for separate checkboxes, we can still reconsider.

@stuartnelson3 would you be able to implement the necessary backend changes? Perhaps have the flexible separate filtering in the API so that the UI is free to decide about separate or joined checkboxes.

[caarlos0]

Working on it...