Switch integer mode default to `bigint`?

[penberg]

Alexey Orlenko asked if there's a reason for integer mode to default to number instead of bigint.

[CodingDoug]

@honzasp and I discussed that BigInts are in no way "normal" for JS devs to deal with, and would likely cause more troubles than problems solved if they were the default for row data. If this is the case, then it only makes sense for people to opt into them when they are prepared for the extra effort involved in understanding and dealing with them.