Use the DsnParser to handle the url option

[stof]

The DsnParser tool is used in the ConnectionFactory to support the url option (the processing is done in the same way than the deprecated logic in DBAL's DriverManager).

As the goal of Symfony is to be compatible out-of-the-box with cloud providers, we always register a default mapping of schemes to DBAL drivers instead of forcing to use DBAL driver names directly, as this is unlikely to happen. For instance, the Postgresql project defines URI-based connection strings that can use postgres or postgresql as scheme, so cloud providers that are not tied to Doctrine DBAL only will use one of those for sure. But DBAL has drivers named pgsql and pdo_pgsql depending on the extension name. However, unlike the old DBAL logic which forced the choice of which of the drivers is used for those standard schemes (which was the reason to deprecate those aliases in DBAL itself in favor of a configurable DsnParser), the bundle allows to configure the driver used for each scheme. The configured schemes are merged with the default map (and they win over our default map).

Closes #1665