(bsfez) Revert "[ENH] Trackers, DynamicList: Add button to Select/Unselect all item of the dynamic list"

This reverts commit 10d84c7b
(robertokir) [REL] Preparing 21.0 release
(robertokir) [REL] Update README file for 21.0
(robertokir) [REL] Update copyright.txt for 21.0
(robertokir) [REL] SecDB for 21.0
(robertokir) [REL] Closing 21.0 release