contrib; dracut: flatten zfs-load-key, simplify zfs-env-bootfs

Upstream-commit: fec2c613a49192942200d26bd20bf434649687b7
Upstream-change: drop 90zfs/module-setup.sh.in cleanups that don't apply
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13291