Icinga DB: Include object names in runtime deletion events

Is your feature request related to a problem? Please describe.

Icinga 2 currently sends only the respective object IDs when sending runtime deletion events, which was fine till now, since Icinga DB only needed that hash ID to delete the respective objects from the database. However, since Icinga DB (Go) will now be used as Icinga Notifications source as well, the ID alone isn't enough to construct the respective object that can be used to close the corresponding incident in Icinga Notifications. For that to work, we would've to either always pre-select the objects from the database before they're completely removed (before performing the respective delete queries) or Icinga 2 includes the respective object name in the deletion event. Since patching Icinga 2 wouldn't require a hard dependency on the Icinga DB (Go) side, @nilmerg prefers the latter option, thus I'm opening this issue for it here.

Start by locating where Icinga 2 emits runtime deletion events and inspect the existing payload that contains only object IDs. Update the event data so the respective object name is included, then verify that deletion events provide enough information for Icinga Notifications to close incidents without pre-selecting deleted objects.