Add README.md to the root.

README.md

+KSystemStats
+============
+
+KSystemStats is a daemon that collects statistics about the running system.
+
+<!--
+SPDX-FileCopyrightText: 2021 Arjen Hiemstra <ahiemstra@heimr.nl>
+SPDX-License-Identifier: BSD-2-Clause
+-->