Features:
+* redefine /var/lib/extensions/ as the dir one can place all three of sysext,
+ confext as well is multi-modal DDIs that qualify as both. Then introduce
+ /var/lib/sysexts/ which can be used to place only DDIs that shall be used as
+ sysext
+
* in pid1: move out all cgroup state settings from Unit into a new object
CGroupState or so which is allocated when we realize the unit into a cgroup,
and then remains referenced by it. The new object should also carry an fd to