`lastInsertRowid` should respect `intMode` config

[कारतोफ्फेलस्क्रिप्ट™]

lastInsertRowid is currently hard-coded to return BigInt here and here.

This creates a mismatch in Id types when intMode is set to number or string.

I'd be glad to send a PR to fix this, but before I do I just want to check with you folks, if this change would make sense to you.