Our search dialog isn't as full featured as packagekits, so just call
out to that. This was originally avoided because it doesn't full
provide the semantics we want, but it's close enough and saves us
from duplicating all their work.
And drop a whole bunch of legacy dbus fallback stuff. Now that we
are bumping the host dependencies to very recent gtk, none of the
back compat should matter.
Despite being a known quantity, autotools is so overkill for our needs,
so let's drop it and replace it with a much simpler and easy to customize
system.
