Docs: Mark User as Super admin in MongoDB to run talawa-admin locally

[lakshz]

Describe the bug
https://github.com/PalisadoesFoundation/talawa-admin/blob/develop/INSTALLATION.md#talawa-admin-registration
This section in the documentation doesn't say about marking the user as super admin in the database to log in locally.

To Reproduce
Steps to reproduce the behavior:

See https://github.com/PalisadoesFoundation/talawa-admin/blob/develop/INSTALLATION.md#talawa-admin-registration

Expected behavior
We should mention a link to https://github.com/PalisadoesFoundation/talawa-api/blob/develop/INSTALLATION.md#manually-adding-the-first-super-admin-user. This section in INSTALLATION.md of talawa-api, clearly describes how to mark the user as super admin

Screenshots
Following is the screenshot of current documentation

[lakshz]

I can fix this. Please assign it to me

[palisadoes]

This is covered in the API documentation which you have to setup prior to installing Admin.

• https://github.com/PalisadoesFoundation/talawa-api/blob/develop/INSTALLATION.md#setting-up-env-last_resort_superadmin_email-parameter

Closing. If you disagree, let me know.