APNs tokens are provided by the client in hex, and we store them in
hex. The existing code which attempts to "validate" them by parsing
them as base64 only works because base64 is a superset of hex.
Enforce that APNs tokens are hex, and remove all of the pieces of test
code which were incorrectly passing them in as base64 strings.
This commit adds a zilencer endpoint to let self-hosted
servers register push devices to whom mobile push notifications
will be sent.
POST "/api/v1/remotes/push/e2ee/register"
Payload: realm_uuid, push_account_id, encrypted_push_registration,
bouncer_public_key
The post request needs to be authenticated with the server’s API key.
Note: For Zulip Cloud, a background fact about the push bouncer is
that it runs on the same server and database as the main application;
it’s not a separate service.
So, as an optimization, we plan to directly call the
`do_register_remote_push_device` function and skip the HTTP request.
