Implements a degraded state detection for LavalinkClusterNode

[SKProCH]

When the socket looses the connection to node, clustered node status should became Degraded. When connection established again, status should return back to Available.

I'm actually doesn't quite happy with the implementation, since SocketConnectionReady kinda duplicates already existent ready task in socket, but at the moment when socket fires the ConnectionClosed, LavalinkNode doesn't recreate the ready TaskCompletitionSource yet, so awaiting it in cluster node will be immediately completed.

[github-actions]

Delta Summary

Generated on:	09/11/2024 - 22:14
Description	Previous	Current	Delta
Coverage date:	09/08/2024 - 16:46	09/11/2024 - 22:14
Line coverage:	66.5%	66.4%	-0.1%
Covered lines:	14692	14700	8
Coverable lines:	22092	22106	14
Total lines:	60549	60577	28
Branch coverage:	51.1%	51.2%	0.1%
Covered branches:	2512	2514	2
Total branches:	4909	4909	0
Method coverage:	Feature is only available for sponsors