Feature: Introduce Super Admins (#705)

* Feature: Introduce Super Admins

- added new devise model for super user
- added administrate gem
- sample dashboards for users and accounts

Co-authored-by: Pranav Raj Sreepuram <pranavrajs@gmail.com>

.env.example

@@ -73,10 +73,6 @@ RAILS_LOG_TO_STDOUT=true
 LOG_LEVEL=info
 LOG_SIZE=500
 
-# Credentials to access sidekiq dashboard in production
-SIDEKIQ_AUTH_USERNAME=
-SIDEKIQ_AUTH_PASSWORD=
-
 ### This environment variables are only required if you are setting up social media channels
 #facebook
 FB_VERIFY_TOKEN=