[5.7] Ability to disable register route

[Cannonb4ll]

Sometimes you will want to disable registering in a application, this PR makes it possible to easily disable those routes.

Auth::routes(['register' => false]);

[JeroenBoesten]

I feel this should've been added a long time ago, needed this more than once, and it seems like a viable option since email verification now works in the same way.

[sisve]

This sounds like something that should have tests. It sounds like a security problem if a dev sets up a site, disable registering, and we accidentally include the register routes again.

On a separate note, should the password reset also have this type of toggle?

[devcircus]

Never understood why you would hide routes behind a method anyway. Your routes file should be explicit. Quicker to do it manually than to use this new option, if you know how to use your editor.

[browner12]

yah, I personally would prefer we got rid of Auth::routes(), but I don't think that's happening anytime soon.

[yajra]

Thanks @Cannonb4ll, sent a related PR #19452 but failed. Glad this went through! Less codes with clean implementation at least for me. No more if to toggle register. :)

Auth::routes([
    'verify'   => true
    'register' => config('site.registration', true),
]);

[shadoWalker89]

@yajra yeah me too,
Done the same exact thing a long time ago #16961