feat(mon-pages): wire the all hosts label filters

The label, tag and contact group columns each offer the values a host
actually carries, at most eight of them per column and with the
prefix entry on. Labels and tags are picked key first, then value.

The contacts column is left alone: no autocompleter serves users, so
it has nothing to offer yet.

CMK-38149

Change-Id: If443e7078d04704926c0abae8f506632a30d9d23