util-linux: one package per binary (pt 1: base_sbindir)

util-linux: one package per binary (pt 1: base_sbindir)

Now that we have required infrastructure in place, we
can start creating one package per binary.

To make this process easier to follow, this is done
in steps, starting with binaries from base_sbindir.

Existing packages (and current dependency by main package):
* agetty
* blkid
* cfdisk <- RRECOMMENDS
* fdisk <- RRECOMMENDS
* fsck
* fstrim
* losetup <- RDEPENDS
* hwclock
* sulogin <- RDEPENDS
* swaponoff <- RDEPENDS
* switch-root <- RRECOMMENDS

New packages:
* blockdev
* ctrlaltdel
* mkswap
* nologin
* pivot-root
* swapon
* swapoff

swaponoff is empty now and simply depends on swapon swapoff

To avoid breaking existing users, all the new packages
are added to the main package as RRECOMMENDS_${PN}, so
they are pulled into existing images etc.

The existing RDEPENDS_${PN} will need some further
clean-up in the future, as it appears a bit random which
packages the main package depends on vs. recommends.
Existing packages that aren't in RDEPENDS / RRECOMMENDS
haven't been added to RRECOMMENDS for that reason.

[YOCTO #13058]

Signed-off-by: André Draszik <andre.draszik@jci.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>