CCLE-4052 - Removed "UCLA" from class/variable names.

- ucla_syllabus_manager -> syllabus_manager
- ucla_syllabus -> syllabus
- ucla_public_syllabus -> public_syllabus
- ucla_private_syllabus -> private_syllabus

(Constants defined in locallib.php)
- UCLA_SYLLABUS_ACCESS_TYPE_PRIVATE -> SYLLABUS_ACCESS_TYPE_PRIVATE
- UCLA_SYLLABUS_ACCESS_TYPE_LOGGEDIN -> SYLLABUS_ACCESS_TYPE_LOGGEDIN
...
- UCLA_SYLLABUS_ACTION_CONVERT -> SYLLABUS_ACTION_CONVERT

- some comments reworked