feat: remove muted

[aintnostressin]

This PR aims to remove muted object from codebase.
Clients relying on this feature should fetch data directly from homeservers.

this is a breaking change for existing clients

---

Required pubky-app changes before this can be merged:

• refactor(mute)!: use muted stream as source of truth instead of relationships model pubky-app#1391
• replace user stream from nexus with homeserver call, pubky/pubky-app@fa313b8
• refactor(mute)!: use muted stream as source of truth instead of relationships model pubky-app#1391

[aintnostressin]

I'll update docs/files/pubky-nexus.tldr too.

[ok300]

LGTM, but I'd wait for @tipogi 's ACK before merging

[tipogi]

Nice! ready for my side

[tipogi]

Nice! ready