Generalize fuse snapshot dirs implemetation

+ allow "/" in tags and snapshot template

cmd/restic/cmd_mount.go

@@ -5,7 +5,6 @@ package main
 
 import (
 	"os"
-	"strings"
 	"time"
 
 	"github.com/spf13/cobra"
@@ -86,9 +85,6 @@ func runMount(opts MountOptions, gopts GlobalOptions, args []string) error {
 	if opts.SnapshotTemplate == "" {
 		return errors.Fatal("snapshot template string cannot be empty")
 	}
-	if strings.ContainsAny(opts.SnapshotTemplate, `\/`) {
-		return errors.Fatal("snapshot template string contains a slash (/) or backslash (\\) character")
-	}
 	if len(args) == 0 {
 		return errors.Fatal("wrong number of parameters")
 	}