Improve logging for gossip messages

### Problem description

We recently encountered a scenario where we faced an error from the beacon API endpoint.

```
error: Failed to send out exit message "PublishError.InsufficientPeers"
```

During the debugging, we could not find any such error been logged anywhere. The `validator-ejector` called the beacon API, which internally called the libp2p-gosshipsub, and that error was raised there and then triggered back to API response, and not logged any where in our code.

### Solution description

We should improve the logging for the gossip messages:

1. Log all invocation any gossip message to any topic
2. Log success or error for any publishing message to any topic

### Additional context

Having those logs on the debug level would be sufficient.