rpc: Remove SetAlias and add Alias to GetInfo Response

This commit removes the SetAlias RPC function because it was deemed
unnecessary. This commit also populates the Alias field in the GetInfo
response

rpcserver.go

@@ -1141,6 +1141,7 @@ func (r *rpcServer) GetInfo(ctx context.Context,
 		Testnet:            activeNetParams.Params == &chaincfg.TestNet3Params,
 		Chains:             activeChains,
 		Uris:               uris,
+		Alias:              nodeAnn.Alias.String(),
 	}, nil
 }