finish refactorting attribute flattening to support reverse group lookup
without a correspondingn group definition in memory.json, as well as
without any instance or type definition in network.coffee; all that we
really need to match is datacenter and env

HOWEVER this assumes that each group has a unique env, or that we're ok
with the first group found with matching env. Of course, the human still
confirms this in the case of adding new servers.
its no longer necessary to remember group for each new instance
assume to assimilate on ssh tcp/22 for new machines during assemble;
its just more convenient this way. then we don't have to memorize a
port which is basically the preferred default on every machine,
even though they all start with tcp/22 when new vms are created