feat: Checkbox for marking those task which are done.

[Chaitanya31612]

There can be a checkbox for every individual task and when clicked the particular task text should get a line through and it should go at the end of the list with lighter text, also the button of edit should be disabled when the checkbox is checked.

I'd like to work on this once approved.

[Chaitanya31612]

@garimasingh128 can you review this issue.