Add a tool to list contents of .img file

list_image <img> lists the contents of the file.

For example:
  $ m microdroid
  $ list_image <path to microdroid.img>
  ./
  ./apex/
  ./bin
  ..

Bug: 195425111
Bug: 225121718
Test: list_image .img
Change-Id: I7c4fca184751ba20066fd25fa4c366a955dbabf6