Function createAppletRelayBackend

createAppletRelayBackend(
pool: ApplesaucePool,
tiers: RelayTiers,
): RelayPoolServiceOptions
Options for kehto's createRelayPoolService over the shared applesauce pool.

Publishes go to the tier selected for the event's kind, so a profile update lands on discovery relays and a note on the user's outbox plus the super tier.
Parameters
- pool: ApplesaucePool
  The shared applesauce pool.
- tiers: RelayTiers
  Relay tiers used to route publishes and unhinted subscriptions.
Returns RelayPoolServiceOptions
Options for createRelayPoolService.
Example
```
runtime.registerService('relay', createRelayPoolService(createAppletRelayBackend(pool, tiers)));
```