Add multi-host support

This refactoring includes:
- added multi-host mode support;
- added support for graceful shutdown of the service;
- added support to flush the log buffer as it fills;
- D-Bus service xyz.openbmc_project.HostLogger replaced with SIGUSR1
  signal handler;
- self diagnostic messages now registered via phosphor-logging;
- added unit tests;
- build system migrated from autotools to meson;
- source code aligned with OpenBMC conventions.

Change-Id: If6c1dfde278af685d8563450543a6587a282c7e4
Signed-off-by: Artem Senichev <a.senichev@yadro.com>
diff --git a/src/version.hpp.in b/src/version.hpp.in
new file mode 100644
index 0000000..99fe644
--- /dev/null
+++ b/src/version.hpp.in
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (C) 2020 YADRO
+
+#pragma once
+
+#define HOSTLOGGER_VERSION "@VCS_TAG@"