[Feature] Support multiple client IDs

[sonicdoe]

When using Sign in with Apple for both an iOS app and a web app, you cannot use the same client ID. As described in the Apple Developer Documentation, web services require a separate Services ID, which is distinct from an App ID. Since AppleAuth only allows configuring one apple_client_id, this scenario is currently a bit tricky to satisfy.

[gabriel]

Added PR to pull out static config here:
#38