Since create_hypertable() allows you to optionally specify a
partitioning column, it makes sense to default to one partition when
no column is specified and asking for the number of partitions when a
column is specified and the number of partitions is not (instead of
defaulting to one).
This patch also changes the order and type of partitioning-related
input arguments to create_hypertable() so that the number of
partitions can easily be specified alongside the partitioning column
and without type casting.
Allowing database deployments that use the same database for both the
meta and node roles simplifies operations when iobeamdb is deployed on
a single-node. It allows the database to operate without any
cross-network communication (either through dblink or postgres_fdw) and
thus offers stronger consistency guarantees.
