DSU to support zip files

DSU previously only supports gzipped system images. This CL enables
DSU to also read zipped files. If there are multiple images in the
zipped release, DSU will install them all.

Bug: 134353973
Test: adb shell am start-activity \
    -n com.android.dynsystem/com.android.dynsystem.VerificationActivity \
    -a android.os.image.action.START_INSTALL \
    -d https://dl.google.com/developers/android/qt/images/gsi/aosp_arm64-QP1A.190771.020-5800535.zip \
    --el KEY_USERDATA_SIZE 8589934592
Test: adb shell am start-activity \
    -n com.android.dynsystem/com.android.dynsystem.VerificationActivity \
    -a android.os.image.action.START_INSTALL \
    -d file:///storage/emulated/0/Download/aosp_crosshatch-img-eng.pchsueh.zip \
    --el KEY_USERDATA_SIZE 8589934592

Change-Id: I9c2137d4d81398a9c6153df63a29c16eb8339795