build: tools: Add json collection of installed files with hashes.

Adds installed-files.json in addition to installed-files.txt
Further sorts the file list to be ordered within the same size bucket.

Test: manual, cross-checked checksums with sha256sum utility
      checked build outputs.

Bug: 19988819
Merged-in: Ifb632eb4df65ec48645c8f93e36bae44ccc52ba8
Change-Id: Ifb632eb4df65ec48645c8f93e36bae44ccc52ba8
Signed-off-by: Sasha Levitskiy <sanek@google.com>