[postgresql] Add SSL Mode support

[DarrylWong]

Currently, postgresql-async reads in a user, password, port, host, and database, from the environment but does not read in any details regarding ssl. This causes it to default to sslmode=disable causing issues if SSL connections are enforced.

https://github.com/jasync-sql/jasync-sql/blob/master/postgresql-async/src/test/java/com/github/aysnc/sql/db/integration/ContainerHelper.kt#L26-L30

It would be nice if there was added support to read and configure SSLConfiguration similar to #337 but for postgresql. Thanks!

[github-actions]

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[oshai]

Contribution is welcome!