Support Stratum Authentication #138
Description
Use case: Datum Gateway running on a VPS with the Sv1 port exposed to the internet. While there's probably nothing wrong in principle if someone finds your endpoint and uses it to mine to their own address I'd prefer to have the option to restrict access.
The Stratum v1 protocol already defines a password that most pools ignore (including Ocean in their legacy Sv1 endpoints). However if the stratum.password key was present in the config and was a non-empty string, the gateway could enforce it.