bug#41927: gio mount unusable on many setups, likely caused by missing dependencies

[raingloom <raingloom@riseup.net>]

On machine A which is running i3wm inside the default gdm, i can use
`gio mount` without any issue, with gvfs is installed globally.

On machine B which is running sway inside sddm or without a display
manager, it invariably fails with "volume doesn't implement mount".
Yes, the hostname is correct, yes it can reach it over the network.
Connecting with sshfs works, but gio with the sftp protocol does not.

I tried installing fuse as well, looked for any kind of dependency i
missed, but couldn't find anything. I'm pretty tired and angry that
something that should be trivial doesn't work. I mostly blame GVFS, but
it would be really nice if it was documented somewhere what the hell
people are supposed to install to get their file managers working.

Based on conversations on IRC, others are also having this problem and
they also couldn't find a solution.

Could someone who knows what the hell GVFS is doing help with this? I'd
really like to avoid installing the entirety of Gnome just to mount some
folders.