Add configuration option for dialects without multi row insert support

[lovetodream]

This change adds a configuration parameter (SQLDialect.supportsMultiRowInsert) to support dialects that do not support multi row inserts (e.g. Oracle). This is true by default. If false, a warning will be logged once multiple rows are about to be inserted into the database within a single statement.

[lovetodream]

It might be more appropriate to throw an error, because the statement will most likely fail anyways. I'd like to hear some opinions about this.

[gwynne]

Closing this out due to age and the existing difficulty of dealing with lack of support for various other features by specific databases.