Add customer actions hook and appointment creation functionality

- Implement customer ID assignment in the appointment creation process.
- Create a new partial for customer actions to render appointment links.
- Add localization for the "Add Appointment" label.
- Introduce CustomerActionsHookListener to manage customer actions rendering.

app/views/customer_appointments/_customer_actions.html.erb

@@ -0,0 +1,4 @@
+<p>
+<% customer = context[:customer] %>
+<%= link_to l(:label_add_appointment), new_customer_appointment_path(customer_id: customer.id), target: :_blank, id: :appointment_link %>
+</p>