s4:dsdb Rework modules create new partitions at runtime

s4:dsdb Rework modules create new partitions at runtime

This is done by passing an extended operation to the partitions module
to extend the @PARTITION record and to extend the in-memory list of
partitions.

This also splits things up into module parts that belong above and below
repl_meta_data

Also slit the partitions module into two files due to the complexity
of the code

Andrew Barltett