move os_image funcs into new file

Author: mirkoCrobu

pkg/flasherapi/flasherapi.go pkg/board/os_image.gopkg/flasherapi/flasherapi.go renamed to pkg/board/os_image.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 flasherapi
+package board
 
 import (
 	"bufio"

pkg/flasherapi/flasherapi_test.go pkg/board/os_image_test.gopkg/flasherapi/flasherapi_test.go renamed to pkg/board/os_image_test.go

@@ -12,7 +12,7 @@
 // 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 flasherapi
+package board
 
 import (
 	"context"