Re-think how we organize error messages

[gajus]

Now that we've introduced driver abstraction, is clear that:

• Slonik must be responsible for standardizing error classes
• Driver must be responsible for mapping errors

However, as the number of errors has proliferated, there is a need to better organize errors. At the very least, we should make it clear which errors are originating from the driver VS from within Slonik client.

We should also add abstraction for common error types, e.g. I noticed P0001 is missing.