phosphor-health-monitor: add new D-Bus interface

This commit introduces following changes -
- A new Metrics Value Interface.
- An interface to reset the metrics, if needed.
- Common Threshold interface so it can be used in Metrics and Sensors.

For more detail, please refer to design -
https://gerrit.openbmc.org/c/openbmc/docs/+/64917

Unit Test: meson build passes.

Change-Id: I014a047f9db6fe470124baa41dcce93caf7ceb4b
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/gen/xyz/openbmc_project/Common/Threshold/meson.build b/gen/xyz/openbmc_project/Common/Threshold/meson.build
new file mode 100644
index 0000000..0bf3482
--- /dev/null
+++ b/gen/xyz/openbmc_project/Common/Threshold/meson.build
@@ -0,0 +1,15 @@
+# Generated file; do not modify.
+generated_sources += custom_target(
+    'xyz/openbmc_project/Common/Threshold__cpp'.underscorify(),
+    input: [ '../../../../../yaml/xyz/openbmc_project/Common/Threshold.interface.yaml',  ],
+    output: [ 'common.hpp', 'server.cpp', 'server.hpp', 'aserver.hpp', 'client.hpp',  ],
+    depend_files: sdbusplusplus_depfiles,
+    command: [
+        sdbuspp_gen_meson_prog, '--command', 'cpp',
+        '--output', meson.current_build_dir(),
+        '--tool', sdbusplusplus_prog,
+        '--directory', meson.current_source_dir() / '../../../../../yaml',
+        'xyz/openbmc_project/Common/Threshold',
+    ],
+)
+