Add storage utilization functions

1. Add "path" in HealthConfig for storage and inode functions.
2. Add storage and inode functions to calculate each utilization by
   "path" (filesystem path).

Tested: verified the storage object path will auto generate when
bmc_health_config.json setting correct and collect the storage utilization.

Signed-off-by: Bruce Lee <Bruce_Lee@quantatw.com>
Change-Id: I4a8fb51b5e85190f908a40d9bf0545ec8167923a
diff --git a/bmc_health_config.json b/bmc_health_config.json
index 398e547..1f9e4f7 100644
--- a/bmc_health_config.json
+++ b/bmc_health_config.json
@@ -30,5 +30,19 @@
             "Target": "reboot.target"
         }
     }
+  },
+  "Storage_RW" : {
+    "Path" : "/run/initramfs/rw",
+    "Frequency" : 1,
+    "Window_size": 120,
+    "Threshold":
+    {
+        "Critical":
+        {
+            "Value": 85.0,
+            "Log": true,
+            "Target": "reboot.target"
+        }
+    }
   }
 }