Add toolbx to OS root

[flibitijibibo]

While not terribly interesting for most end users, it'd be very helpful to have this when trying to set up a native developer environment directly on Deck hardware. The Steam Runtime SDK docs recommend it...

https://gitlab.steamos.cloud/steamrt/sniper/sdk/-/blob/steamrt/sniper/doc/podman.md

... and podman/flatpak are already on the system. The Arch package supposedly adds ~10.6MB to the root, which seems worth it IMO since the whole point of toolbx is that it can run unprivileged and installing it manually kind of ruins that.

[bertogg]

Hi, the OS already ships distrobox as an alternative to toolbx

[flibitijibibo]

Oh, huh - I'll take a look soon. Should this be mentioned in the steamrt docs somewhere?

[flibitijibibo]

Filed a steam-runtime issue: ValveSoftware/steam-runtime#739

So I guess this is mostly a conversation between SteamOS and the SLR SDK, happy to try things out as this develops.