Allow windows (userless/passwordless) authentication for SQL Server

fix code style

Adding Windows Authentication compatibility according to http://php.net/manual/en/function.sqlsrv-connect.php
"By default, the connection is attempted using Windows Authentication. To connect using SQL Server Authentication, include "UID" and "PWD" in the connection options array."

Fetch all should use the driver statement's fetchAll method

Use locked version of PHPStan to avoid accidental build failures

Lost parameters: wrong ESCAPED_BRACKET_QUOTED_TEXT

The first capturing group of the parser regex was stopping form the moment it would find a `[` character.

postgres: correctly produce alter table sql comment to update column definition

Updated PHPUnit to 7.4

remove ClassLoader

Implemented handling BLOBs represented as stream resources for IBM DB2

Trying to fix failing DB2 builds

Currently, builds like https://travis-ci.org/doctrine/dbal/jobs/440354436 are failing do to an APT issue. Trying to update APT packages as per support recommendation.

Removed link to www.doctrine-project.org from doc blocks

Implemented proper escaping of string literals in platforms and schema managers

Deprecated regex-based asset filters

Implement {Configuration#getSchemaAssetsFilter}

Test against the latest stable sqlsrv extension

Fixed coding standard violations in the codebase

Updated doctrine/coding-standard to 5.0, 

See https://github.com/squizlabs/PHP_CodeSniffer/issues/2165