zfs/debian: add packaging files

based on Debian's packaging work, but simplified:
- no DKMS
- no dracut
- no udebs

and remove old patches which were based on top of Debian's packaging.

Reviewed-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Tested-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

zfs/debian/tree/zfs-initramfs/usr/share/initramfs-tools/conf.d/zfs

@@ -0,0 +1,8 @@
+for x in $(cat /proc/cmdline)
+do
+	case $x in
+		root=ZFS=*)
+			BOOT=zfs
+			;;
+	esac
+done

zfs/debian/tree/zfs-initramfs/usr/share/initramfs-tools/hooks/zdev

@@ -0,0 +1,67 @@
+#!/bin/sh
+#
+# Add udev rules for ZoL to the initrd.
+#
+
+PREREQ="udev"
+PREREQ_UDEV_RULES="60-zvol.rules 69-vdev.rules"
+COPY_EXEC_LIST="/lib/udev/zvol_id /lib/udev/vdev_id"
+
+# Generic result code.
+RC=0
+
+case $1 in
+prereqs)
+	echo "$PREREQ"
+	exit 0
+	;;
+esac
+
+for ii in $COPY_EXEC_LIST
+do
+	if [ ! -x "$ii" ]
+	then
+		echo "Error: $ii is not executable."
+		RC=2
+	fi
+done
+
+if [ "$RC" -ne 0 ]
+then
+	exit "$RC"
+fi
+
+. /usr/share/initramfs-tools/hook-functions
+
+mkdir -p "$DESTDIR/lib/udev/rules.d/"
+for ii in $PREREQ_UDEV_RULES
+do
+	if [ -e "/etc/udev/rules.d/$ii" ]
+	then
+		cp -p "/etc/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
+	elif [ -e "/lib/udev/rules.d/$ii" ]
+	then
+		cp -p "/lib/udev/rules.d/$ii" "$DESTDIR/lib/udev/rules.d/"
+	else
+		echo "Error: Missing udev rule: $ii"
+		echo "       This file must be in the /etc/udev/rules.d or /lib/udev/rules.d directory."
+		exit 1
+	fi
+done
+
+for ii in $COPY_EXEC_LIST
+do
+	copy_exec "$ii"
+done
+
+if [ -f '/etc/default/zfs' -a -r '/etc/default/zfs' ]
+then
+	mkdir -p "$DESTDIR/etc/default"
+	cp -a '/etc/default/zfs' "$DESTDIR/etc/default/"
+fi
+
+if [ -d '/etc/zfs' -a -r '/etc/zfs' ]
+then
+	mkdir -p "$DESTDIR/etc"
+	cp -a '/etc/zfs' "$DESTDIR/etc/"
+fi