Please implement client auth as defined in nip 42. This is also needed for #17.

I am primarily interested in my relay requiring auth at some point. Only serve REQ from

1. paying users
2. their follows
3. their follows follows
4. everybody else. (no auth would count as everybody else)

But ... as clients don't support nip42, the very first step is to let users auth without caring with which key they auth and maybe notify them that auth failed without consequences, to get client devs moving on this topic.

As mentioned in the comments below, full nip-42 support could also mean support for sync and stream.

• strfry relay supports nip42
• strfry stream supports nip42
• strfry sync supports nip42