Re-work router

[staab]

• NIP 66 based bootstrapping instead of NIP 65
• Implement scenarios more granularly (publish vs request, multiple heuristics, heuristic overrides)

Something like this:

const RouterContext = {
  getOutboxRelays: async (pubkey: string) => string[]
  getInboxRelays: async (pubkey: string) => string[]
}

const outboxHeuristic = async (pubkey: string) => {
  return RouterContext.getOutboxRelays(pubkey)
}

const inboxHeuristic = async (pubkey: string) => {
  return RouterContext.getInboxRelays(pubkey)
}

const publicBroadcastHeuristic = async (event: SignedEvent) => {
  return uniq([
    await outboxHeuristic(event.pubkey),
    await Promise.all(getTagValues("p", event.tags).map(inboxHeuristic)),
  ])
}