busybox: Make various commands more compatible

With OpenHarmony tests using some of our busybox commands, this should help us
not having to fight quite as much fallout from busybox CLI being different
from normal (and/or toybox) CLI.

Signed-off-by: Esben Haabendal <esben.haabendal@huawei.com>

recipes-core/busybox/busybox/openharmony.cfg

+CONFIG_DESKTOP=y

recipes-core/busybox/busybox_%.bbappend

+# SPDX-FileCopyrightText: Huawei Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
+SRC_URI += " \
+	file://openharmony.cfg \
+"