refactor(example): use barrel import for auth module

[goenning]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/ngrx/platform/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[X] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

related to #1684

What is the new behavior?

This PR introduces barrel imports for auth module and its sub-folders.

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

While doing this change, I noticed some unused variables on auth specs. This PR also removes them. If this is not OK, I can issue a separate PR just for that.

[ngrxbot]

Preview docs changes for 4e9954c at https://previews.ngrx.io/pr1808-4e9954c/

[timdeschryver]

Hi, thanks for the PR!
I think we should also create an index file for auth/models?

What about also exporting the components/containers/effects as an array? Not saying we should, just throwing it here 😅

(Taken from Todd Motto)

[ngrxbot]

Preview docs changes for 4aff96c at https://previews.ngrx.io/pr1808-4aff96c/

[goenning]

Good point, I've add barrel imports to auth/models now.

As for the array of components, IMHO that'd be too much for the amount of components the example app has. I imagine it could also be confusing for newcomers who are not used to that.

[timdeschryver]

LGTM
fyi, I have triggered another build for the failing docs

[timdeschryver]

🤦‍♂️ because of the cleared cache, we now have the same build problem as in #1795 (comment) ( will be solved once #1795 gets merged)