Moved a batch of function from commands/* subpackage to commands

This commit is preparatory to move all the implementation of
ArduinoCoreService interface directly as methods of ArduinoCoreService.

The goal is to turn ArduinoCoreService into a proper implementation instead
of being a mere proxy to global functions.

Author: cmaglie

commands/instances.go

@@ -43,8 +43,6 @@ import (
 	"google.golang.org/grpc/status"
 )
 
-var tr = i18n.Tr
-
 func installTool(pm *packagemanager.PackageManager, tool *cores.ToolRelease, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) error {
 	pme, release := pm.NewExplorer()
 	defer release()

commands/lib/search_matcher.go renamed to commands/libraries_index_search_matcher.go

@@ -13,7 +13,7 @@
 // Arduino software without disclosing the source code of your own applications.
 // To purchase a commercial license, send an email to license@arduino.cc.
 
-package lib
+package commands
 
 import (
 	"strings"