[dataimport] fix doc string to stop referring to the old API

[dataimport] drop duplicate init of MassiveObjectStore.sql

[dataimport] remove implicit commits from MassiveObjectStore Let the user decide when to commit the transaction.

[dataimport] drop extra indirection through MassiveObjectStore._initialized dict We already have self.__dict__, no need to add another one for a static set of keys.

[dataimport] remove remaining references to dataio from MassiveObjectStore In particular, rename metadata tables to live in the ^cw.* namespace.

[dataimport] rename logger from dataio.massiveimport to dataimport.massive_store

[dataimport] remove commit_at_flush parameter from MassiveObjectStore WARNING: the default value was True, but flush() now never commits.

[dataimport] remove autoflush_metadata from MassiveObjectStore parameters Hopefully not needed.

[dataimport] remove uri_param_name from MassiveObjectStore parameters It doesn't belong here.

[dataimport] turn iid_maxsize into a class attribute

[dataimport] turn eids_seq_{start,range} into class attributes Only the master-mode store will actually use eids_seq_start to reset the eid sequence.

[dataimport] remove replace_sep parameter from massive store It is unused since changeset efbbf1e93a04 "[dataimport] Properly escape strings sent to COPY FROM"

[dataimport] remove pg_schema parameter from massive store It can be recovered from the system source's configuration.

[dataimport] remove drop_index parameter from massive store "drop_index=False" also implied not dropping any constraints, in particular foreign keys, which meant any attempt to import entities would fail, because we only add metadata (the entities table) after the entity's insertion.

[dataimport/test] update call to ucsvreader Silences warning: [3.20] 'separator' kwarg is deprecated, use 'delimiter' instead