Enforced parameter and return value types in Connection classes

Add proper types to Doctrine\DBAL\Types namespace.

Add types to Schema namespace

Enforced parameter and return value types in Platform classes

Enforced parameter and return value types in Driver classes

Removed Driver::getName()

The method is not used for anything else than skipping tests for specific drivers. Cross-driver portability should be established by drivers, not outside of them based on their name.

Remove @​deprecated stuff

Enforced parameter and return value types in Statement classes

Remove deprecated AbstractSchemaManager::getFilterSchemaAssetsExpression(), Configuration::getFilterSchemaAssetsExpression() and Configuration::getFilterSchemaAssetsExpression()

`Connection::ping()` will now return `void`

Remove user provided PDO functionality

Improve consistency of exception message formatting.

Extract exception factory methods into specific exceptions

Implemented support for persistent connections in PDO and mysqli drivers

Extract Doctrine\DBAL\DBALException::notSupported()
Extract Doctrine\DBAL\DBALException::invalidPlatformVersionSpecified()
Extract Doctrine\DBAL\DBALException::invalidPdoInstance()
Extract Doctrine\DBAL\DBALException::invalidWrapperClass()
Extract Doctrine\DBAL\DBALException::invalidDriverClass()
Extract Doctrine\DBAL\DBALException::invalidTableName()
Extract Doctrine\DBAL\DBALException::noColumnsSpecifiedForTable()
Extract Doctrine\DBAL\DBALException::typeExists()
Extract Doctrine\DBAL\DBALException::typeAlreadyRegistered()
Extract Doctrine\DBAL\DBALException::typeNotRegistered()
Extract Doctrine\DBAL\DBALException::unknownColumnType()
Extract Doctrine\DBAL\DBALException::typeNotFound()
Extract Doctrine\DBAL\DBALException::invalidPlatformType()
Extract Doctrine\DBAL\DBALException::driverRequired()
Extract Doctrine\DBAL\DBALException::unknownDriver()
Extract Doctrine\DBAL\DBALException::invalidColumnIndex()
Extract Doctrine\DBAL\Exception\ConnectionException::commitFailedRollbackOnly()
Extract Doctrine\DBAL\Exception\ConnectionException::noActiveTransaction()
Extract Doctrine\DBAL\Exception\ConnectionException::savepointsNotSupported()
Extract Doctrine\DBAL\Exception\ConnectionException::mayNotAlterNestedTransactionWithSavepointsInTransaction()
Extract Doctrine\DBAL\Exception\InvalidArgumentException::fromEmptyCriteria()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailed()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedFormat()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedInvalidType()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedSerialization()
Extract Doctrine\DBAL\Query\QueryException::unknownAlias()
Extract Doctrine\DBAL\Query\QueryException::nonUniqueAlias()
Extract Doctrine\DBAL\Sharding\ShardingException::notImplemented()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDefaultFederationName()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDefaultDistributionKey()
Extract Doctrine\DBAL\Sharding\ShardingException::activeTransaction()
Extract Doctrine\DBAL\Sharding\ShardingException::noShardDistributionValue()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDistributionType()
Extract Doctrine\DBAL\Cache\CacheException::noCacheKey()
Extract Doctrine\DBAL\Cache\CacheException::noResultDriverConfigured()
Extract Doctrine\DBAL\Schema\SchemaException::tableDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::indexNameInvalid()
Extract Doctrine\DBAL\Schema\SchemaException::indexDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::indexAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::columnDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::namespaceAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::tableAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::columnAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::sequenceAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::sequenceDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::uniqueConstraintDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::foreignKeyDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::namedForeignKeyRequired()
Extract Doctrine\DBAL\SQLParserUtilsException::missingParam()
Extract Doctrine\DBAL\SQLParserUtilsException::missingType()
Drop Doctrine\DBAL\DBALException::invalidPlatformSpecified()
Drop Doctrine\DBAL\DBALException::limitOffsetInvalid()
Drop Doctrine\DBAL\Schema\SchemaException::alterTableChangeNotSupported()

Fix UniqueConstraint with empty name.

Added type hints to the Column class