Add splits to table at table creation.

Add capability to add table splits at table creation. Recent changes now allow iterator and locality groups to be created at table creation. Do the same with splits. Comment below from ACCUMULO-4806 explains the motivation for the request:

etcoleman added a comment - 2 hours ago
It would go al long way if the splits could be added at table creation or when table is offline.  When the other API changes were made by Mark, I wondered if this task could also could be done at that time - but I believe that it was more complicated.

The delay is that when a table is created and then the splits added and then taken offline there is a period proportional to the number of splits as they are off-loaded from the tserver where they originally got assigned.  (The re-online with splits distributed across the cluster is quite fast)

If the splits could be added at table creation, or while the table is offline so that the delay for shedding the tablets could be avoided, then the need to perform the actual import offline would not be as necessary.