Submission of systemd after unfork in SP2

- Import commit ac52edce0f820ffefa5110b6fc4b03e35bf68d61
96a7639970 udev/net-id: Fix check for address to keep interface names stable (#8458) (bsc#1168076)
ce5953a877 login: use free_and_replace() and TAKE_PTR()
e5190b4b51 logind: remove manager_start_slice()
cdeb8d1a48 logind: use free_and_replace in one spot
109aac4b67 logind: drop unnecessary braces
9194610e7e systemd-mount: don't check for non-normalized WHAT for network FS (bsc#1165011)
12b63cb73a systemd-mount: allow to specify an arbitrary string for arg_mount_what when vfs is used (bsc#1165011)

- Import commit 7c246f16a6358516a586629091375ee5d45739ec
2205963ee2 manager: fix job mode when signalled to shutdown etc (bsc#1161262)
e9b76da147 manager: remove fallback for user/exit.target
fa4a1155e7 man: dbus method Manager.Exit() does not start exit.target
dc0ec526f2 units: do not install rescue.target for alt-↑
e3ba383bf8 Add %j/%J unit specifiers

- Replace 60-ssd-scheduler.rules with 60-io-scheduler.rules from TW
This adds support for I/O scheduler selection with blk-mq
(bsc#1165579, bsc#1164717).

- Add 60-ssd-scheduler.rules
This rules file which select the default IO scheduler for SSDs is
being moved out from the git repo since this is not related to
systemd or udev at all and is maintained by the kernel team.

- Import commit 7e52d0c21a0c895d4f0ae2319f1eb4f2246147ba
eedd149d6c core: coldplug possible nop_job (bsc#1139459)
09405f8eee Revert "udev: use 'deadline' IO scheduler for SSD disks"
57cab4a328 Fix typo in function name
f846231c1a polkit: when authorizing via PK let's re-resolve callback/userdata instead of caching it (bsc#1162108 CVE-2020-1712)