db845c: installer: Add bootloader binaries and flashing scripts

* Add AOSP flashing and board recovery scripts, a README for
  instructions and prebuilt flashing tool (qdl) for board recovery.
  QDL source is hosted at
    https://github.com/andersson/qdl/commits/master (760b3dffb03d)

* Also added the db845c aosp bootloader binaries from here:
  https://snapshots.linaro.org/96boards/dragonboard845c/linaro/rescue/26/

  Build description:
    Build URL: https://ci.linaro.org/job/lt-qcom-bootloader-dragonboard845c/26/
    Linux proprietary bootloaders package: RB3_firmware_20190529180356-v3.zip

    ABL source code: https://git.linaro.org/landing-teams/working/qualcomm/abl.git/commit/?id=5086ee1aa38de6d69efea1d4a5ee535203014097
    Partition table:
      AOSP: https://git.linaro.org/landing-teams/working/qualcomm/db-boot-tools.git/tree/dragonboard845c/aosp/partition.xml?id=0e8dde66a17cad7040b7f21f9e752fc1ee13006d

Change-Id: I563b09779ef506b529774bd0b32147d8d516f096
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
56 files changed