gluon-announce: Remove now unused collect.lua
The file promotes the probably unnecessary re-execution of the announce
scripts. Instead, gluon-announced should be queried using
gluon-neighbour-info -d ::1 -p 1001 -t0 -r nodeinfo
if both gluon-announced and gluon-neighbour-info are present. But to not
depend on any of those, no script for this one-liner is provided.