PgClient: support multi hosts connection

#### Describe the feature

[here](https://github.com/eclipse-vertx/vertx-sql-client/blob/master/vertx-pg-client/src/main/java/io/vertx/pgclient/impl/PgConnectionUriParser.java#L42) I saw that we cannot connect to a multi hosts instance of postgres which is mandatory for us.

Can you plan supporting multi hosts connection ?

#### Use cases

Use case: Support high availbility postgresql instances

As an example, with the classic jdbc driver, we can define this property to connect to our HA postgres instance:
```
quarkus.datasource.jdbc.url=jdbc:postgresql://my.host-1.com,my.host-2.com,my.host-3.com:5432/myDB?targetServerType=master&ssl=true&sslmode=verify-ca&sslcert=my-cert&sslkey=my-key&sslpassword=&sslrootcert=my-cert.crt
```

It would be great to be able to do the same with your PgClient by parsing the URI the same way