Compile update_engine_sideload as a static recovery program.

This patch converts update_engine_sideload to a statically linked
program and installs it in the recovery image. The resulting program
uses a statically linked boot_control HAL instead of relying in
libhardware to dynamically load it.

The static library or libraries needed for the boot_control HAL need to
be specified by the product with the new make variable
PRODUCT_STATIC_BOOT_CONTROL_HAL. Otherwise, a stub implementation is
included and update_engine_sideload will fail at runtime.

Bug: 27178350
TEST=`make dist` builds a recovery image with update_engine_sideload in it.

Change-Id: I1f624ecd29220ac2237e42da0a636ea0a015a78e