Dell S6000,S6100 system health changes (sonic-net#6788)

Needed support for platform system health in Dell platforms

device/dell/x86_64-dell_s6000_s1220-r0/system_health_monitoring_config.json

@@ -0,0 +1,11 @@
+{
+	"services_to_ignore": [],
+	"devices_to_ignore": [],
+	"user_defined_checkers": [],
+	"polling_interval": 60,
+	"led_color": {
+		"fault": "amber",
+		"normal": "green",
+		"booting": "blinking green"
+	}
+}

device/dell/x86_64-dell_s6100_c2538-r0/system_health_monitoring_config.json

@@ -0,0 +1,11 @@
+{
+	"services_to_ignore": [],
+	"devices_to_ignore": [],
+	"user_defined_checkers": [],
+	"polling_interval": 60,
+	"led_color": {
+		"fault": "amber",
+		"normal": "green",
+		"booting": "blinking green"
+	}
+}

platform/broadcom/sonic-platform-modules-dell/s6000/sonic_platform/chassis.py

@@ -341,6 +341,9 @@ def get_change_event(self, timeout=0):
                     return True, ret_dict
         return False, ret_dict
 
+    def initizalize_system_led(self):
+        return True
+
     def set_status_led(self, color):
         """
         Sets the state of the system LED

platform/broadcom/sonic-platform-modules-dell/s6100/sonic_platform/chassis.py

@@ -372,6 +372,9 @@ def get_change_event(self, timeout=0):
 
         return True, ret_dict
 
+    def initizalize_system_led(self):
+        return True
+
     def set_status_led(self, color):
         """
         Sets the state of the system LED

platform/broadcom/sonic-platform-modules-dell/z9332f/sonic_platform/psu.py

@@ -113,7 +113,7 @@ def get_voltage(self):
         if not is_valid:
             return None
 
-        return "{:.1f}".format(voltage)
+        return float(voltage)
 
     def get_voltage_low_threshold(self):
         """
@@ -159,7 +159,7 @@ def get_current(self):
         if not is_valid:
             return None
 
-        return "{:.1f}".format(current)
+        return float(current)
 
     def get_power(self):
         """
@@ -173,7 +173,7 @@ def get_power(self):
         if not is_valid:
             return None
 
-        return "{:.1f}".format(power)
+        return float(power)
 
     def get_powergood_status(self):
         """