Remove usage of disqus_disable_mobile as it isn't supported anymore.

Added support for disqus_disable_mobile:
https://github.com/angrycodr/disqus-for-drupal8/pull/20

I see two ways in which we can implement disqus_category_id (https://help.disqus.com/customer/portal/articles/1261676-using-categories)

1. We create categories (using api) according to the bundle name of the entity to which the disqus field is present. Adding disqus_category_id as field-level setting and all the field instance to this entity will have the same category.
(For eg. for content type 'article', the disqus category will be article).
Since creating categories require disqus api, this method would be an advantage as fewer api calls will be required and also it would much simpler to understand that disqus[category] = entity[bundle]

2. We give a field instance option 'category' while creating or editing an entity. the user will specify a category( sports, politics,etc), so it gives a bit of flexibility in categorizing comment. But why give the site's user the trouble to specify a comment category seperately ? Also there is no real implementation or any widget provided by disqus related to disqus_category_id, maybe in future we can provide views in drupal filtering with disqus categories.

First method seems better; wont be providing any form element for it. On field creation, just calling the api method categories->create on the bundle name string. The category will remain default 'General' if api is not installed.

pull request for implementing disqus_category_id according to the first method as I stated above :

https://github.com/angrycodr/disqus-for-drupal8/pull/35

this page no longer lists disqus_disable_mobile. Maybe we should remove it too.

Any news on Disqus categories?!
(I am interested in Drupal 7 atm..)

I have modified the scope of this issue and removed the settings and feature-related mobile optimized version. Thanks everyone for working on this.