Added route for adding bulk user

[Raman-pro]

Implement User Authentication and Bulk Creation Features

Changes:

• Added route for adding bulk user accessible to user with permission 0.

Security:

• Password hashing using bcrypt
• and only authorised user with permission 0 can access the route

Documentation:

• Added JSDoc comments for /post-add-users

[Shobhit141141]

The controller function requires some changes.

After making the requested changes in this review, please also check the PR for add by CSV in nix-frontend by @godaralokesh29. He has already created the frontend functionality to add multiple users via CSV.

• In that PR, remove the for loop that adds users one by one and instead use + test your API directly.
• (For later) In the current manual signup of a single user, he has also introduced role assignment while adding a new user. You can update the signup API later to accept and store the role of the newly added user.

[Raman-pro]

There is a bug with roles assignment I will update it by today making sure the CSV of roles of user gets updated and not the default role gets assigned

[Raman-pro]

Hey I have added functionality for adding roles in /signup as well as /post-add-users please review.

[Shobhit141141]

The /add-members route is working fine however, some error handling needs to be taken care of.

Note: The route is changed from /post-add-users to /add-members.

I have added review comment, please take a look and make the necessary updates.

[Raman-pro]

I have added the asked changes please have a review.