cmd/stdiscosrv: Device access control

[gnotaras]

Currently, the discovery server does not support any access control mechanisms.

IP based access control is technically possible through a reverse proxy or the firewall, but the devices usually have dynamic IP addresses, which makes this solution inefficient.

Adding support for basic/api-key authentication or implement device ID based access control would be useful.

[calmh]

This is not useful to us (the project) as we only run open-for-all discovery servers, but could be fine as a contribution.

[gnotaras]

Hi Jakob,

Indeed, I was thinking about it from the user perspective and had a discovery server with limited access in mind. Thanks for your fast replies!