OpenRC scripts: add configuration file

This allows users to customize the snapshots path to work with, e.g., snapper.
If no path is configured, it will default to timeshift.

Signed-off-by: David P <megver83@parabola.nu>

Makefile

@@ -26,7 +26,8 @@ install:
 	@# OpenRC init system
 	@if test "$(OPENRC)" = true; then \
 		install -Dm744 -t "$(BIN_DIR)/" grub-btrfs-openrc; \
-		install -Dm744 -t "$(DESTDIR)/etc/init.d/" grub-btrfsd; \
+		install -Dm744 grub-btrfsd.initd "$(DESTDIR)/etc/init.d/grub-btrfsd"; \
+		install -Dm644 grub-btrfsd.confd "$(DESTDIR)/etc/conf.d/grub-btrfsd"; \
 	 fi
 	@# Arch Linux like distros only :
 	@if test "$(INITCPIO)" = true; then \
@@ -83,4 +84,4 @@ help:
 	@echo "  INITCPIO  | bool | include mkinitcpio hook        | false"
 	@echo "  SYSTEMD   | bool | include unit files             | true"
 	@echo "  OPENRC    | bool | include OpenRc daemon          | false"
-	@echo
+	@echo