Move tr function in separate file

Author: silvanocerza

commands/board/attach.go

@@ -27,14 +27,11 @@ import (
 	"github.com/arduino/arduino-cli/arduino/cores/packagemanager"
 	"github.com/arduino/arduino-cli/arduino/sketch"
 	"github.com/arduino/arduino-cli/commands"
-	"github.com/arduino/arduino-cli/i18n"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
 	discovery "github.com/arduino/board-discovery"
 	"github.com/arduino/go-paths-helper"
 )
 
-var tr = i18n.Tr
-
 // Attach FIXMEDOC
 func Attach(ctx context.Context, req *rpc.BoardAttachRequest, taskCB rpc.TaskProgressCB) (*rpc.BoardAttachResponse, error) {
 	pme, release := commands.GetPackageManagerExplorer(req)

commands/board/board.go

@@ -0,0 +1,20 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package board
+
+import "github.com/arduino/arduino-cli/i18n"
+
+var tr = i18n.Tr