Merge branch 'preprod' into 'master'

app/controller/admin.php

app/controller/perso.php

app/view/backend/contreparties.html

app/view/backend/user.html

db/migrations/20181213125806_add_parent_field.php

db/seeds/CounterpartSeeder.php

src/LQDN/Command/CounterpartCreateCommand.php

src/LQDN/Finder/CounterpartFinder.php

src/LQDN/Handler/CounterpartHandler.php

src/LQDN/Handler/UserHandler.php

tests/functional/Finder/CounterpartFinderTest.php

tests/functional/Handler/CounterpartHandlerTest.php

tests/functional/Handler/UserHandlerTest.php