feat(disk): show the storage disk in file managers

A plain fstab entry is invisible to Thunar and friends — they list
removable media and gvfs entries, so the disk could only be reached by
typing its path. x-gvfs-show puts it in the sidebar, and because the entry
is noauto it appears as a drive that is not mounted yet, which is what it
usually is.

Note when changing this: the gvfs volume monitor reads fstab at startup,
so an already-running one has to be restarted before the entry shows up.

modules/disk.nix

@@ -42,6 +42,12 @@ let
     "x-systemd.device-timeout=5"
     "x-systemd.mount-timeout=10"
     "x-systemd.idle-timeout=600"
+    # Without this the disk is reachable only by typing its path: file managers
+    # list removable media and gvfs entries, not plain fstab lines. Since the
+    # entry is noauto, it shows up as a drive that is not mounted yet, which is
+    # what it usually is.
+    "x-gvfs-show"
+    "x-gvfs-name=Storage"
   ];
 
   storageSubvolumes = {