* 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
* adding support for ONLY keyword for PostgreSQL as an optional flag of from() and into() through table(tableName, only)
* passing only parameter from default function was missing
* changing only option to options object with only key
* better style per @wubzz suggestion