Connection status tracking

[KitsuneRal]

As of now, all network requests try to reach the server independently. This leads to suboptimal operation when the server is unreachable - all jobs retry on their own, some fail, some (sync) keep trying. It would probably make sense to use the sync loop to track connection health at the same time, so that, e.g., message sending jobs could just patiently wait instead of pushing the network on their own.