Fix Shipping discount with percentage

Shipping discount with percentage must be calculated after shipping selection.
Use getAlias
Add symfony/expression-language as dependency
The methods should be after the attributes
Fix CS
Merge pull request #1058 from aRn0D/php-cs-fixer

[ResourceBundle] Fix CS
Merge pull request #1057 from aRn0D/method-order

The methods should be after the attributes
Merge pull request #1052 from umpirsky/fix/variable-product-repository-alias

Use getAlias
Merge pull request #1053 from abimus/fix/expression-language-deps

[ResourceBundle] Add symfony/expression-language as dependency
Merge pull request #1051 from ramol/master

Fix Shipping discount with percentage