Make better use of dracut functions when building initramfs

Setting up the module involves multiple redundant calls to a bunch of
dracut functions wheich can be combined into one. Additionally, the mass
of code required to load libgcc_s.so* can be replaced with one dracut
function. This has the additional effect of removing errors involving
the non-installation of libgcc_s.so* which are seen on debian bullseye
when using version 2.1.2-1~bpo11+1 from the backports repository.

The systemd binaries are separated out into their own dracut_install
function call so they do not get pulled in when dracut does not load the
systemd module.

Reviewed-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Andrew J. Hesford <ajh@sideband.org>
Signed-off-by: Savyasachee Jha <hi@savyasacheejha.com>
Closes #13010