Make sure all request parameters are used by the script, otherwise trigger the error 404 page (see #4277)
Added a switch to determine whether an `Input::setGet()` parameter will be checked (see #4277)
Do not initialize `$arrUnusedGet` with the `$_GET` array
Merge branch 'socketconnection' of https://github.com/dominikzogg/contao into feature/mysql-sockets

Conflicts:
	system/modules/core/templates/be_install.html5
Add the English label for the socket field
Merge branch 'feature/mysql-sockets' into develop
Merge branch 'feature/check-request-string' into develop

Conflicts:
	system/modules/core/library/Contao/Input.php
Make all static methods of the `Input` class public (see #3382)
Add the `File::sendToBrowser()` method (see #4696)
Add the redirect status code 307 to `System::redirect()` (see #5375)
Moved `Controller::prepareForWidget()` to `Widget::setAttributesFromDca()`.

Make sure to always call the inherited method of the specific widget class and
not the one of the parent class:

```
// Wrong
new TextField(Widget::setAttributesFromDca(…));

// Correct
new TextField(TextField::setAttributesFromDca(…));
```

See #4697 for more information.
Move the new vendor files from their old location to the new one
Optionally pass the `DataContainer` object to `Widget::getAttributesFromDca()`
Move the `Pagination` class into the `library` folder (see #4726)
Move `System::parseDate()` to `Date::parse()`
Move `System::getModelClassFromTable()` to `Model::getClassFromTable()`
Do not extend the `System` class if not required
Do not require `DcaExtract` to inherit from `Database\Installer`
Do not require `ZipWriter` to inherit from `System`
Make `Controller::loadDataContainer()` public static