ExifInterface: implement the serialzation for Exif IFD structures

One image can have multiple image file directories, which stores the
attributes of the image, in Exif specification to save metadata.
In the old version, the all attributes from several image file
directories were combined in a one hash map eventually and were served
without distinction of the original IFD group.

In order to keep the original data as much as possible, it loads/saves
the attributes based on the original IFD group internally.

Bug: 26044456, Bug: 11224701
Change-Id: I416e4e79fd47461c9aa83ce13591ed1a5d42f26e