Make sure that students with external LMS role Learner get enrolled in platform course.

[ztraboo]

Added log statements when user is authenticated with the platform during the lti_launch function.

Learner Course Enrollment
In order to count unique students for our own analytic purposes, we're make sure that these anonymous LTI users get enrolled in the course. We're also assuming that the course_mode is set to honor mode because most of our courses offer certificates of completion.

The functionality that edX provides ignores this course enrollment.

Special Instructions For Instructor Roles
In order to make sure the the instructor has full access rights to EducateWorkforce Instructor Dashboard and analytic tools we'd still want to register their platform accounts with Instructor/Staff roles.

To prevent duplicate instructor accounts, we follow these steps to ensure uniqueness:

• Register instructors directly in EducateWorkforce course as we have been doing with the Instructor/Staff role.
• Only perform course enrollments for students in the Canvas course. They'll come in anonymously to the platform but they'll be enrolled the first time they launch the lti_provider link.
• Should an instructor be registered on Canvas directly and not EducateWorkforce, then that account will come in anonymously to EducateWorkforce, but it won't count towards our unique students/instructor count because we're not calling the CourseEnrollment.enroll() method.

[ztraboo]

Merged this in without waiting for unit tests to complete. This change needs to go out to production soon because of all of the current Canvas requests from Choose Aerospace.