Convert hilogd into a systemd service

- Patch hilogd to use sd_notify(3) to send ready notification to systemd, and
  thus use as a Type=notify service.
- Add log and logd users and groups, with similar uid and gid as in OHOS.
- Place Unix sockets in /run/openharmony/hilog instead of /dev/unix/socket,
  enabling secure creaton and managing of these.
- Use systemd.socket units for the two Unix sockets, to allow creating with
  desired uid/gid and permissions, and allowing to use hilogd with systemd
  socket activation

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