<!--- 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 -->

required: false
    aliases: [ account_username ]
    description:
      - Username of account to add/delete/modify
    type: str
    version_added: "2.8"
  new_password:
    required: false
    aliases: [ account_password ]
    description:
      - New password of account to add/modify
    type: str
    version_added: "2.8"
  roleid:
    required: false
    aliases: [ account_roleid ]
    description:
      - Role of account to add/modify
    type: str
    version_added: "2.8"
  bootdevice:
    required: false
    description:
      - bootdevice when setting boot configuration
    type: str
  timeout:
    description:
      - Timeout in seconds for URL requests to OOB controller
    default: 10
    type: int