Pass server name to after_connect block

I'm currently checking for the host of the server on the `after_connect` callback to apply different settings to it (eg: set a longer statement timeout for a read-only follower). This is obviously pretty fragile and doesn't work when multiple databases are running on the same host, so here I'm proposing that we also pass the database name to `after_connect`.

By keeping the param order I believe this is backwards compatible.