Feature: Include Learning Plan and Competency Events

[davidpesce]

As of Moodle 3.1 the concept of learning plans and competencies has been added:

• https://docs.moodle.org/33/en/Learning_plans
• https://docs.moodle.org/33/en/Competencies

The following events seem like a good start to adding this functionality:

• \core\event\competency_plan_viewed
• \core\event\competency_plan_review_started
• \core\event\competency_plan_completed
• \core\event\competency_viewed
• \core\event\competency_framework_viewed

[nadavkav]

There are also some potentially interesting user competency events that should be implemented too: https://github.com/moodle/moodle/tree/master/lib/classes/event competency_user_competency_*

[davidpesce]

Cleaning up old issues.