API design considerations:

1. Driver::connect() is an adapter between the DBAL Connection::connect() and the Driver\Connection::__construct() APIs. It should do all conversion of the parameters and not leak array $params into the connection.
2. Driver\Connection::__construct() is a tiny wrapper over the underlying driver's "connect" function. Its API should be as close to the "connect" function as possible but not too close to have to leak the underlying connection resource back to the driver like it happens in some PDO drivers:

   1. dbal/src/Driver/PDOPgSql/Driver.php

      Line 38 in ae8c720

      $connection->getWrappedConnection()->setAttribute(PDO::PGSQL_ATTR_DISABLE_PREPARES, true);

   2. dbal/src/Driver/PDOSqlite/Driver.php

      Lines 43 to 47 in ae8c720

      	$pdo = $connection->getWrappedConnection();
      	foreach ($this->_userDefinedFunctions as $fn => $data) {
      	$pdo->sqliteCreateFunction($fn, $data['callback'], $data['numArgs']);
      	}

      
      In order to avoid the leakage but not to have too many parameters in MySQLi connection constructor either, a concept of connection initializers has been introduced. It can be thought of as an implementation of the Builder or Functional Options pattern.

Additional changes:

1. The custom error handler in MySQLi connection has been removed in favor of an error suppression operator. The error handler would yield the same results but required maintenance and a dedicated unit test that doesn't pass on Windows. Additionally, it masked improper usage of $connection->sqlstate in case of a connection failure (should help fixing mysqli::$sqlstate is inaccessible on a failed/non-initialized connection since PHP 8 #3947).
2. $supportedDriverOptions have been removed from the MySQLi connection. Whether the option is supported will be determined by the call to mysqli_options(). The previous approach led to improper error handling around mysqli_options() because an error was impossible to reproduce.

Although the code implementing secure MySQLi connection has been modified, it's not tested as it never was. It should be possible to set up a build job using cyprien/mysql-tls on Travis later.

Fixes #4069