Allow setting multiple RPC node connections as fallback

[boecklim]

Instead of only allowing to set one SV node for RPC connection in the configuration, it should be possible to set additional RPC connections as a fallback in case that the RPC calls fail.

arc/config/example_config.yaml

Lines 27 to 31 in d1bf693

	peerRpc: # rpc configuration for bitcoin node
	password: bitcoin
	user: bitcoin
	host: localhost
	port: 18332

In case the RPC call fails, the RPC call would then just be sent to the next SV node available in the configuration

This would improve the reliability of features that rely on RPC calls