<!--- Verify first that your feature was not already discussed on GitHub -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
This feature would implement a ClearSessions command for the Sessions category of redfish_command, to clear all active sessions.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
redfish_command.py
redfish_utils.py

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->
This command would help user to clear all active sessions.

<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can also paste gist.github.com links for larger files -->

result = {}
        key = 'IndicatorLED'
        payloads = {'IndicatorLedOn': 'Lit', 'IndicatorLedOff': 'Off', "IndicatorLedBlink": 'Blinking'}
        result = {}
        response = self.get_request(self.root_uri + self.chassis_uri)
        if response['ret'] is False:
            return response
        result['ret'] = True
        data = response['data']
        if key not in data:
            return {'ret': False, 'msg': "Key %s not found" % key}
        if command in payloads.keys():
            payload = {'IndicatorLED': payloads[command]}
            response = self.patch_request(self.root_uri + self.chassis_uri, payload)
            if response['ret'] is False:
                return response
        else:
            return {'ret': False, 'msg': 'Invalid command'}
        return result
    def _map_reset_type(self, reset_type, allowable_values):