Handling sequences and identity columns with X100 tables

[hab6]

With Ingres databases, sequences and identity columns work for X100 tables only in specific circumstances and are not recommended for X100 tables. See documentation for additional details.

In cases where sequences or identity columns are used with the Ingres dialect, we may need to raise warnings when there is an X100 backend. Will also need to consider when this applies only to DDL or also to other SQL statements as well.