Config to APNs similar to keyserver, but instead of reading private key from the file we pass it inside JSON (command line or AWS KMS secrets).
Keyserver config: [link](https://github.com/CommE2E/comm/blob/ea0aac2608af297a9d96e467ed80cb2ab8f42361/keyserver/src/push/providers.js#L30).
Depends on D12608