Remove usage of content for relays on kind 3 (Contacts)

[sondreb]

Previously there was non-standard implementations across Nostr clients to use content on the kind 3 event to store relays.

This task is to track the removal of this functionality and instead relying solely on NIP-65 for relay management.

For new users, Notes will attempt to read kind:10002, if not found it will do a one-time lookup for kind:3 and use the relays in content if available. If not, it will continue to use the default relays provided by Notes.

We should probably be a good citizen and restore the content when saving following list, but Notes will no longer support modify this value.

[sondreb]

Add an action in the relay management to publish the user's 10002 to as many relays as possible, perhaps all discovered relays during usage, or a fixed list?