Authentication and LTI OAuth working

This release uses the Devise gem to authenticate 'Admins' this will be the role that registers the TC's in the app.

Devise provides various facilities like :

• User sign up
• User sign in/out
• Protect actions (web pages) selectively, when accessing a page without being logged shows an error message and render the sign in form, if we fill it with correct information, automatically redirect the user to the previously requested page.

Also includes the IMS-LTI gem, this allows OAuth authentication, using this we can get trusted user information and use it to display different views based on roles and another user, context, and TC data.

Included Bootstrap 4 and Font Awesome 5 for future styling

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Screenshots:

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