Shipments filter fix

fixed createdAtFrom, createdAtTo.
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
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
dispatching variant creation event
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
Remove final keyword in SyliusCheckoutEvents.

I want to extend and add more events.
Include promotion total to PayPal gateway.
Set shipment state to onhold before process payment.
Fix currency converter. Use multiply.
fixed spec
Merge pull request #1060 from kayue/patch-5

Remove final keyword in SyliusCheckoutEvents.
Merge pull request #1063 from kayue/patch/order-shipping-state

Set shipment state to onhold before process payment.
Merge pull request #1059 from akovalyov/fix/generator-events

Proper dispatching of variant creation event
Merge pull request #1062 from kayue/patch-6

[BUG] Include promotion total to PayPal gateway.
Resource bundle depend on symfony form.