sys-kernel/bootengine: Make use of ue-rs download_sysext binary

This pulls in
flatcar/bootengine#82 to switch from curl and
decode_payload to the ue-rs download_sysext binary.

Author: pothos

sdk_container/src/third_party/coreos-overlay/sys-kernel/bootengine/bootengine-0.0.38-r26.ebuild renamed to sdk_container/src/third_party/coreos-overlay/sys-kernel/bootengine/bootengine-0.0.38-r27.ebuild

@@ -10,7 +10,7 @@ CROS_WORKON_REPO="https://github.com"
 if [[ "${PV}" == 9999 ]]; then
 	KEYWORDS="~amd64 ~arm ~arm64 ~x86"
 else
-	CROS_WORKON_COMMIT="5295e877b6ebd2fb343e464ffda896534c22d4c3" # flatcar-master
+	CROS_WORKON_COMMIT="7d72eb9a2539c1de6cb34ff3481323895973698e" # TODO: flatcar-master
 	KEYWORDS="amd64 arm arm64 x86"
 fi