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/yaml/xyz/openbmc_project/Inventory/Item.interface.yaml b/yaml/xyz/openbmc_project/Inventory/Item.interface.yaml
index 4ef840b..78cf994 100644
--- a/yaml/xyz/openbmc_project/Inventory/Item.interface.yaml
+++ b/yaml/xyz/openbmc_project/Inventory/Item.interface.yaml
@@ -71,3 +71,10 @@
       reverse_name: powering
       required_endpoint_interfaces:
           - xyz.openbmc_project.Inventory.Item.PowerSupply
+    - name: measured_by
+      description: >
+          Objects that implement Item can optionally implement the 'measured_by'
+          association to provide a link to one or more metrics.
+      reverse_name: measuring
+      required_endpoint_interfaces:
+          - xyz.openbmc_project.Metrics