feat: регистрация продавца (FR-01) + палитра B (зелёный/янтарь)

apps/accounts/urls.py

@@ -0,0 +1,10 @@
+from django.urls import path
+
+from . import views
+
+app_name = 'accounts'
+
+urlpatterns = [
+    path('register/seller/', views.seller_register, name='seller_register'),
+    path('register/seller/done/', views.seller_register_done, name='seller_register_done'),
+]