Add ability to pass jdbc subparams, via the module, in connection uri

In some of our other modules we use the following pattern for this

 $jdbc_ssl_properties = "?ssl=true&sslfactory=org.postgresql.ssl.jdbc4.LibPQFactory&sslmode=verify-full&sslrootcert=${localcacert}"

That is to say maybe instead of the `database_ssl` bool there should just be a string args like `jdbc_ssl_properties` which we construct the subname from and `database_ssl` just equals `jdbc_ssl_properties == ''`.