feat(mon-pages): filter hosts by label and contact

Two conditions the host filter tree had no way to express: a set of
labels or tags, and a set of contacts or contact groups. Both match
when the host carries any one of the values given.

Labels reach Livestatus through the same encoder the classic label
filter uses, so their quoting and key/value semantics are one
behaviour rather than two. A trailing '*' matches by prefix: on the
value through the dict column's regex operator, on a bare key through
the list column that holds the names alone.

CMK-38149

Change-Id: Ifdce15ecd7c219f9e5fa9f55698576ee9cb70003