MDL-62138 core: remove core_register and core_publish

These components have no classes and no strings and have no purspose. Component core_hub is responsible
for storing data, defining classes and strings for site registration and course publishing

This also reverts MDL-61945

lib/classes/component.php

@@ -471,10 +471,8 @@ $cache = '.var_export($cache, true).';
             'plugin'      => null,
             'portfolio'   => $CFG->dirroot.'/portfolio',
             'privacy'     => $CFG->dirroot . '/privacy',
-            'publish'     => $CFG->dirroot.'/course/publish',
             'question'    => $CFG->dirroot.'/question',
             'rating'      => $CFG->dirroot.'/rating',
-            'register'    => $CFG->dirroot.'/'.$CFG->admin.'/registration', // Broken badly if $CFG->admin changed.
             'repository'  => $CFG->dirroot.'/repository',
             'rss'         => $CFG->dirroot.'/rss',
             'role'        => $CFG->dirroot.'/'.$CFG->admin.'/roles',