Opt-Out Feature with FilterJS update (#21)

* Add Opt-Out Feature

- To list all Opt-Out letters
- To send mails to users
- To test mailing feature
- Update background worker to send opt-out mails and update user status as Subscribed
- Add unsubscribed_at field in User modal and updated the rake task
- Add routes for opt-out actions
- Updated the status to 'new user' while creating User

* Add Feature to view users status wise

    - Add Filter.js v2.1.0 for client side filtering
      and rendering of users
    - Remove StreamTable
    - Add navigation-bar, select list and pagination for Users
    - Update UI for User Index template
    - Add scope for all user status

* Rake Task and UI changes

- Add rake task to check and update user status to Subscribe and Unsubscribed
- UI fix the navigation bar, paignation and button alignments
- Fix the rake task for Blocked users and web subscription status

* UI changes

- Add spinner
- Updated batch size to 2000
- Fix UI releated to Edit and Create template
- Styles and Fixes

* Updated JS code to fix issue

+ deleted unwanted files

* Remove unwanted JS files

- Delete FilterJS
- Delete Mustache
- Remove reference of FilterJS and Json_query from application.js
- Remove reference for bootstrap-datepicker-rails

* Fix the subscribe and unsubscribe link

Co-authored-by: Swapnil Chincholkar <[email protected]>

Author: Ashish944

app/assets/javascripts/light/StreamTable.js

@@ -16,7 +16,6 @@
 //= require bootstrap
 //= require bootstrap-datepicker
 //= require select2
-// require bootstrap-datepicker-rails
 //= require redactor-rails
 //= require redactor-rails/plugins
 //= require_tree .