some more unit tests on xml info parser

Depending on the used environment the port might be appended to the host header resulting in an inaccessible instance when initially setting up on a system with a different HTTP or HTTPS port. (for example test:500)

To test this setup ownCloud under a different port with and without this patch. (heads-up: localhost is always white-listed, so use a different domain)

drop files_external tests from autotest - they will be executed with autotest-external.sh which is coming

Currently there is no AppFramework way to modify cookies, which makes it unusable for quite some use-cases or results in untestable code.

This PR adds some basic functionalities to add and invalidate cookies.

Usage:
```php
$response = new TemplateResponse(...);
$response->addCookie('foo', 'bar');
$response->invalidateCookie('foo');
$response->addCookie('bar', 'foo', new \DateTime('2015-01-01 00:00'));
```

Existing cookies can be accessed with the AppFramework using `$this->request->getCookie($name)`.

This is unused legacy code. Let it die with ~~~honor~~ fire.

Fixes https://github.com/owncloud/core/issues/12346

Fixes https://github.com/owncloud/core/issues/12347

This reverts commit 09fd34ee.