[1.0.0] Adopt vincentlanglet/twig-cs-fixer for Twig coding standards

Good opportunity to do those little Twig fixes too.

footer

Use `|default(foo)` filter instead of shorthand ternary `?:`

<a class="fr-footer__brand-link" href="{{ home_url|default('/') }}" title="{{ 'Homepage'|t }} - {{ operator_logo_alt ? operator_logo_alt : service_title }} - {{ logo_text }}">

translate

Unused variables: html_id

Function `random()` must be used in a `default()` filter!

nav_menu

Function `random()` must be used in a `default()` filter!

{% set item_id = 'menu-'~loop.index~'-'~random() %}
{% set item_id = 'mega-menu-'~loop.index~'-'~random() %}