extend DDL syntax for Spider to pass-through to data nodes

Today, if one creates a Spider table, the remote data node tables are named in the spider table definition, but the remotes tables are not created. While that can be useful, in some cases, it is none-the-less surprising that one must also connect to each remote data node and create the tables there as well.

For ALTER TABLE, it is especially surprising that by default the alter does not pass-through to the tables on the data nodes.