- move the "legacy names" system into where we create the module proxy.

- move the "legacy names" system into where we create the module proxy.
This is so that we can do a total open ended "*args, **kw" style translation
for the vast majority of use cases that are using alembic.op, without impacting
docstrings for the Operations class.
There is a risk here of impacting an application that is using Operations
directly instantitaed while using old names.   We may still have to accommodate
that somehow.