Enrolment key based self-registration

This auth plugin combines the best of both email based signup and self enrolment keys into a streamlined process making it much faster for students to get into a course. For the student it saves around 9-10 clicks and avoids context switching between a browser and their email client where they can become easily become disengaged or run into issues if their email is unavailable.
Moodle Enrolment key based self-registration
This is a functional clone of the Email-based self-registration
plugin that also enrols a user into available courses based on a token
supplied. When a user enters a valid token it will automatically enrol
them into the course that token was specified for.
Courses that provide self enrolment can restrict access to them with a
key. If the signup token matches any course enrolment key then the new
user will be enrolled into those courses.
Courses that
provide self enrolment can restrict access to them with a key. If the
signup key matches any course enrolment key then the new user will be
enrolled into those courses.
The streamlined process flow:
(Signup page -> Course)
The normal self registration process flow:
(Signup page -> Confirmation page -> Open email client and click link -> Navigate to course -> Click on enrol -> Enter enrolment key -> Course)