Implement maintenance mode in frontend and integrate to backend

[Rupeshiya]

Present scenario:
There is no design to trigger maintenance mode by admin. So add the toggle button to trigger maintenance mode and integrate that to backend implement API for triggering maintenance.

Expected outcomes:
The admin of the community should able to trigger the maintenance mode and the web view should change accordingly.

Additional context:
Working on it.

[jaskiratsingh2000]

Thanks for opening up the issue.