Move X-Auth-Url logic to auth_url middleware

Refactoring the auth_password middleware to move X-Auth-Url logic
into the auth_url middleware, so that all X-Auth-Url logic is
handled in one place.

This also adds the auth_url middleware in front of the auth_password
middleware, so that there should be no behavior change

Co-Authored-By: Richard Lee <rblee88@gmail.com>
Related-Bug: #1259364
Change-Id: I3819cbf1a4c4955752dc7c804b0add1bab2b962c
Merge "Move X-Auth-Url logic to auth_url middleware"