Git commits in Moodle 3.10.4 by Simey Lameze

commit 94259f8a7df402fce0f0410408131dabedab9a56
Author: Simey Lameze <simey@moodle.com>
Date:   Fri, 16 Apr 2021 11:42:33 +0800
Tag:    v3.10.4

MDL-71156 core: machinery to recover orphaned calendar events