[#28] Make storage node configurable

To run storage node at dev-env environment it should have
configurable parameters. To keep `cfg` structures we can
read configuration from env and yml config file with viper
and parse values such as script hashes, fees, keys into
`cfg` structures.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

cmd/neofs-node/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"log"
 
@@ -14,7 +15,10 @@ func fatalOnErr(err error) {
 }
 
 func main() {
-	c := defaultCfg()
+	configFile := flag.String("config", "", "path to config")
+	flag.Parse()
+
+	c := initCfg(*configFile)
 
 	init_(c)