v1.0.4: WP-15937 [Import] Improve error handling for PostgreSql (#5)

* WP-15937 postgres error handling improvement

* WP-15937 version update

* WP-15937 clean up

* WP-15937 add more case for invalid url

* WP-15937 distinguish hostNotFound vs invalidHost

* WP-15937 fix error message and code for connection failure

* WP-15937 fix error message