Rename the API to be a better description of what it does. Besides, a
subsequent patch will rename virNetworkAssignDef to virNetworkObjAssignDef
so rather than make that patch confusing we'll take the intermittent step
in this patch.
In an effort to be consistent with the source module, alter the function
prototypes to follow the similar style of source with the "type" on one
line followed by the function name and arguments on subsequent lines with
with argument getting it's own line.
Move all the virNetworkObj related API/data structures into their own
modules virnetworkobj.{c,h} from the network_conf.{c,h}
Purely code motion at this point plus adjustments to cleanly build
