rework pipeline group filtering
rework pipeline group filtering

show all nodes in the group, *and* any direct upstream/downstream nodes.

if a node has no groups configured, do not show it in any group. this is
less surprising than having it show up in all groups.

[#80072782] [#80073566]

concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse,concourse/concourse