Support aliases for commerce order user view

Problem/Motivation

commerce_order order entities have two urls, one for admins/"sellers" processing the orders and one for users/customers. As they have defined the canonical url as the admin url it is not possible to create path aliases for the user view urls, which would make sense as well.

The current path template of the entity.commerce_order.user_view route is /user/{user_id}/orders/{commerce_order_id}, which is not very user/customer friendly.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes