Introduce the SchemaManagerFactory interface

[derrabus]

… to allow apps to override the default schema managers

Q	A
Type	feature
Fixed issues	Fixes #5812

Summary

This PR introduces a new interface SchemaManagerFactory that can be implemented by apps that need to override the schema manager. It also ships with two implementations:

LegacySchemaManagerFactory

This factory implements the current and deprecated way of letting the driver create the schema manager. If no factory is configured, we fall back to this implementation.

DefaultSchemaManagerFactory

This factory implements the new way of letting the platform class create the schema manager. This way was introduced by #5458. Configuring DefaultSchemaManagerFactory as factory will allow apps to opt-in to the behavior that we have on the 4.0.x branch.

The factory can be configured through the Configuration class:

$configuration = new Configuration();
$configuration->setSchemaManagerFactory($mySchemaManagerFactory);

$connection = DriverManager::getConnection([/* your connection parameters */], $configuration);