Add an ability to use custom Struct Parser (structMap), missing destination name

[shlima]

Currently, the parser that extracts fields from query rows into the dest structure is private and hardcoded.

Add the ability to use a custom parser or a setting that allows silently skipping the missing destination name error.

Reason: migrations before deployment (ADD COLUMN) — the old code raises an error on queries like SELECT *, whereas it could continue working without any errors.

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Implementation example in pgx and scany (adapter) https://pkg.go.dev/github.com/georgysavva/scany/dbscan#WithAllowUnknownColumns

WithAllowUnknownColumns allows the scanner to ignore db columns that doesn't exist at the destination. The default function is to throw an error when a db column ain't found at the destination.