Requesting - Sign in with Apple as provider

[rishavs]

Hi

Can you please add the support for Apple as a sign in provider?

https://support.apple.com/en-us/HT210318

[msa7]

Hi,
Unfortunately, no fee time on my side. Please open PR.

[stakach]

@rishavs this is now supported via generic oauth
https://github.com/spider-gazelle/multi-tenancy-template/blob/94fc98591f9f7acb1c480af7e71bb222035401b2/src/controllers/auth.cr#L10-L38