Reduce load time in case of ppl with many courses

This commit includeD the following changes:

* REMOVE DB requests and enrol_get_my_courses method usage
* Inrease version
* ADD Arrays for semester containing their courses, optimize sorting of semesters and courses, internal changes to work with new changes
* FIX Error related to missing navigation when user is not yet logged in
* REMOVE Mutliple calls to get_course_metadata
* Prevent array access with empty key
* Change parameter type from int to constant variable