* Make postgres client wrapIdentifierImpl independent of `this` context
* Also fixes a bug where only single digit indices were accepted.
* add customWrapIdentifier helper for client
* customWrapIdentifier is one more level of abstraction for the wrapIdentifier "pipeline"
that allows the custom wrapIdentifier to be called without calling the `wrapIdentifierImpl`
* bufix: use custom wrapIdentifier in columnInfo. fixes#2402