`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

Drop support for feferred misspelling in PostgreSqlPlatform::getAdvancedForeignKeyOptionsSQL()

PostgreSqlPlatform::getAdvancedForeignKeyOptionsSQL()

Reworked AbstractSchemaManager::extractDoctrineTypeFromComment(), removed ::removeDoctrineTypeFromComment()

Removed errorCode() and errorInfo() methods from Connection and Statement APIs

Reworked `AbstractSchemaManager::extractDoctrineTypeFromComment()` removed `::removeDoctrineTypeFromComment()`

Reworked driver exceptions

Removed DB2SchemaManager::_getPortableForeignKeyRuleDef()

Enable strict types

Reworked AbstractPlatform::get*Expression() methods

Modified AbstractPlatform::getLocateExpression() and ::getSubstringExpression() signatures

Changed the type of $char in AbstractPlatform::getTrimExpression()`from string|false to ?string

Connection::quote() can only quote strings

Changed the type of `$char` in `AbstractPlatform::getTrimExpression()` from `string|false` to `?string`

1. The argument is always available since the method is only called from listTableIndexes() which requires a table name.
2. The argument itself seems a workaround and only needed to bypass the fact that the SQLiteSchemaManager violates the method contract: instead of reformatting the provided data it fetches more data from the DB schema which requires a table name. This argument should be dropped completely later.