MDL-46499 navigation: better enrolled course limit

We now user $CFG->navcourselimit to limit the number of
courses shown in the navigation when browsing another users
full profile. Previously it showed all courses which caused
some slowdown.
MDL-47340 action_menu: selector, RTL, consistency fixes
MDL-47838 gradebook: Singleview fix for invalid links.
Merge branch '46499-28' of git://github.com/samhemelryk/moodle
Merge branch 'MDL-47838-master' of git://github.com/zbdd/moodle
Merge branch 'MDL-47340-master' of git://github.com/jethac/moodle
MDL-47513 theme_base: Fix grader report when blocks are docked
MDL-47839 core_grades: Minor styling improvements to setup/user report