Rewrite configuration loading

Rewrited loadConfig() function to walk the project directory
looking for bee.json and Beefile. If no configuration file
found, it fallbacks to the default configuration. In case
of an error, a log message is printed to the console.

run.go

@@ -115,7 +115,7 @@ func runApp(cmd *Command, args []string) int {
 
 	err := loadConfig()
 	if err != nil {
-		ColorLog("[ERRO] Fail to parse bee.json[ %s ]\n", err)
+		ColorLog("[ERRO] Failed to load configuration [ %s ]\n", err)
 	}
 
 	var paths []string