Feature: Check-out registrants

[git-init-priyanshu]

Is your feature request related to a problem? Please describe.
Currently, Talawa has the feature to check in registrants but lacks a check-out feature. This feature is also important for visualizing data through charts, as it will help us see when members are checking in and when they are checking out of the event. This will assist admins in understanding whether event retention is good or not.

Describe the solution you'd like
I would like a feature to check-out the members who have previously checked in to the event.

Additional context
There is already a field called isCheckedOut in the EventAttende schema but it is not used anywhere.

Potential internship candidates
Please read this if you are planning to apply for a Palisadoes Foundation internship PalisadoesFoundation/talawa#359

[git-init-priyanshu]

I would like to work on this. Thanks.

[palisadoes]

@git-init-priyanshu

1. This will need to be an optional feature
2. It cannot be a toggle of check in. Check outs must be tracked separately