feat(mon-services): add the Host and Services page menu dropdowns

The page rendered a bare PageMenu, so it offered none of the entries the
legacy "Services of host" view groups under Host and Services: host
configuration, service discovery, effective parameters, graphs,
notifications, Event Console and availability.

Derive both from get_context_page_menu_dropdowns(), the function the
legacy view itself uses, keeping the host_single and service_multiple
dropdowns it returns. Every entry follows, user-defined visuals
included, and so does the permission and edition gating.

Two things that reuse needs. The availability entry defaulted to the
current URL plus mode=availability, which this page cannot render, so
callers may now pass a URL and this one points at the legacy view. Host
labels are read because link_from conditions match on the first row, the
same reason the legacy view reads that column.

Unlike the all-hosts page this keeps the auto-appended "display"
dropdown: its only entry is the kiosk-mode toggle, which the Vue app
does not replace and which is the only way back out of kiosk mode.

CMK-37972

Change-Id: Ib8ad250acdc7b7b48d7dec083b8a369233a5dd70