Improve sdcard partitioning process

-Improve code for partitioning sdcards
-Allow user to select a device for partitioning (must be removable)
-Use sgdisk to partition sdcards
-Set default sizes for ext and swap to 0
-Change increments for ext to 256MB and swap to 64MB

Note: sgdisk is included in 6.0. I have included a static prebuilt
sgdisk for trees that do not have sgdisk, however the prebuilt
sgdisk is a decent bit larger than the old parted binary. The old
parted binary is quite old at this point and we only have it for
armv7a. sgdisk should be maintained by AOSP and can be built from
source so it should work across architectures.

Change-Id: Ib80882d9b5776e5e9358b11340fba392e6f1ae09