TYPO3 Core

Problem:
With the integration of #20733 the feature has been added to select/deselect all checkboxes in the install tool db comparer with a single click. The problem is:
a) This only works for all checkboxes, you can't only check the "Add fields" checkboxes for instance.
b) It only works in the install tool, but should work in the extension manager too.

Solution:
attached patch adds a checkbox for each group of modification that contains more than one change. By moving the functionality from typo3/sysext/install/mod/class.tx_install.php to t3lib/class.t3lib_install.php this works in the extension manager too.

This is a follow-up to #20733
(issue imported from #M11544)