Add Speakers Emails Endpoint

[giuseppeman]

There is a "secret" Endpoint in the sessionize-API for retrieving the speaker-emails.
The Request to this endpoint looks like this:

https://sessionize.com/api/v2/<Event-ID>/view/SpeakersEmails?s=<secret hash>

Note: the secret Hash is a special key that is only available/retrievable for unlocked admins (Contact Sessionize-Support to get unlocked)

The return value is a list of the speakers with their email-address.
Example from a test-event:
[ { "id": "00000000-0000-0000-0000-000000000000", "firstName": "Sophia", "lastName": "Test", "email": "test0@sessionize.com" }, { "id": "00000000-0000-0000-0000-000000000004", "firstName": "Aiden", "lastName": "Test", "email": "test4@sessionize.com" } ]

Please implement this missing endpoint to the client.