demo-dashboard-gateway-image: Add image

This image is part of the dashboard gateway demo and is meant to run on
the linux based target running HomeAssistant.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

meta-ohos-demo/recipes-core/images/demo-dashboard-gateway-image.bb

+require recipes-core/images/openharmony-image-base.bb
+
+SUMMARY = "Dashboard demo image: gateway"
+DESCRIPTION = "Home Assistant based image targeting a gateway device"
+LICENSE = "Apache-2.0"
+
+IMAGE_INSTALL_append = "\
+	python3-appdaemon \
+	python3-homeassistant \
+	"
+
+# 100 MiB of additional storage for config and runtime data.
+IMAGE_ROOTFS_EXTRA_SPACE = "102400"
+
+# This is a workaround in case the build runs on ZFS with compression on.
+# It also gives us extra runtime space.
+IMAGE_OVERHEAD_FACTOR = "2"