Allow access to all metadata

[mauvm]

This can be done by changing the authQuery of the ConCaVa MySQL adapter to:

SELECT users.* FROM users
LEFT JOIN user_tokens ON user_tokens.user_id = users.id
LEFT JOIN user_devices ON user_devices.user_id = users.id
LEFT JOIN devices ON devices.id = user_devices.device_id
WHERE user_tokens.token = :token
AND (devices.udid = :udid OR users.is_admin = 1)
LIMIT 1`

In this way all admin accounts can pass the authentication step of ConCaVa.