In detail:

Renamed legacymsg::RmcProxyImpl to legacymsg::RmcProxyTpcIp
Renamed legacymsg::VdqmProxyImpl to legacymsg::VdqmProxyTcpIp
Renamed legacymsg::VmgrProxyImpl to legacymsg::VmgrProxyTcpIp
Renamed legacymsg::DummyVmgrProxy to legacymsg::VmgrProxyDummy
Renamed legacymsg::DummyVdqmProxy to legacymsg::VdqmProxyDummy
Renamed legacymsg::DummyRmcProxy to legacymsg::RmcProxyDummy

Bottom-line, if the concrete sub-class of a pure abstract class can have
a meaningful name without the need to use the Impl or Implemention
suffix then avoid using the suffix.

This commit also renames the "Dummy" proxy classes so that they are
easier to see when their source code directory is listed
alphabetically.