docs: https://github.com/nostr-protocol/nips/blob/master/05.md

guide using an own domain: https://nvk.org/n00b-nip5

using github pages: https://mutatrum.com/nostr-verification-through-github-pages/

transform npub to hex: https://nstr.cloud/key.html or log in with the npub at https://iris.to and copy from the settings.