platform-mc: Add sensor manager

Added sensor_manager class. The sensor_manager class manages the timing
of sensor polling.

tested: Verified on ast2600 EVB which is connected to a PLDM device
over I2C. bmcweb can display the state of numeric sensor.

Signed-off-by: Gilbert Chen <gilbert.chen@arm.com>
Signed-off-by: Thu Nguyen <thu@os.amperecomputing.com>
Change-Id: I4257f823ea26d7fdb322cc82d847e94db056258c
diff --git a/platform-mc/test/meson.build b/platform-mc/test/meson.build
index 6b95f90..64177cc 100644
--- a/platform-mc/test/meson.build
+++ b/platform-mc/test/meson.build
@@ -4,6 +4,7 @@
             '../terminus.cpp',
             '../platform_manager.cpp',
             '../manager.cpp',
+            '../sensor_manager.cpp',
             '../numeric_sensor.cpp',
             '../../requester/mctp_endpoint_discovery.cpp'],
             include_directories: ['../../requester', '../../pldmd'])
@@ -12,6 +13,8 @@
   'terminus_manager_test',
   'terminus_test',
   'platform_manager_test',
+  'sensor_manager_test',
+  'numeric_sensor_test',
 ]
 
 foreach t : tests