chore(app): migrate to new authentication infrastructure

This commit updates the admin app to the reworked authentication
infrastructure.

Performed changes:

* Replace

<resolve: {
    authenticatedUser:
AuthenticationServiceProvider.requireAuthenticatedUser,
}>

with

<authentication: 'required'>

* Remove <AuthenticationServiceProvider> from route config
* Replace <authenticatedUser> in route controller with <authentication>

* Replace <if-logged-in> with <cam-if-logged-in>
* Replace <if-logged-out> with <cam-if-logged-out>

* Replace <authentication.user.*> in templates + controllers with
<authentication.*>

Related to CAM-2507