openthread: Gateway blueprint OTBR configuration

Ensure we enable packet forwarding for IPv6 and IPv4. This is needed
for a serving OpenThread network as well as WiFi AP services .

Signed-off-by: Stefan Schmidt <stefan.schmidt@huawei.com>

meta-ohos-blueprints/recipes-connectivity/openthread/ot-br-posix/60-otbr-ip-forward.conf

+net.ipv6.conf.all.forwarding = 1
+net.ipv4.ip_forward = 1

meta-ohos-blueprints/recipes-connectivity/openthread/ot-br-posix_%.bbappend

+FILESEXTRAPATHS_prepend := "${THISDIR}/ot-br-posix:"
+
+SRC_URI_append = "file://60-otbr-ip-forward.conf"
+
+do_install_append() {
+    install -d ${D}${sysconfdir}/sysctl.d/
+    install -m 0644 ${WORKDIR}/60-otbr-ip-forward.conf ${D}${sysconfdir}/sysctl.d/
+}