[distributed] a number of ctor infra cleanups
1. We're no longer synthesizing the local
init. All designated inits of a dist actor
must have exactly one ActorTransport parameter.
This parameter is used in the init's prologue
to initialize some of its members.
2. We're synthesizing a factory function for
the resolve initialization, instead of an
actor-member named `init` to serve that
purpose.
As such, much of the earlier infrastructure
is no longer needed, etc.
