[Todo] Check support for Steam versions

[dwatteau]

Steam sells some LucasArts titles, such as Indy3, Indy4, Loom, The Dig or Sam & Max. Some of them are a bit different from the original floppy/CD releases (which is what GOG mostly uses).

The ScummTR tools predate the Steam versions, which appear to embed the index files (000.LFL and so on) into the main executables.

(For example, for my Steam version of Loom, 000.LFL is at offset 170464+8307 of the Loom macOS binary file.)

I don't think that the ScummTR tools should to find this content themselves, but we should at least document how to do this somewhere.

References:

https://github.com/symm/LAAExtract
https://github.com/scummvm/scummvm/blob/master/engines/scumm/detection_steam.h

Games to be checked:

• [ ] Loom (Steam/Windows)
• [x] Loom (Steam/macOS)
• [ ] Indy3 (Steam/Windows)
• [ ] Indy3 (Steam/macOS)
• [ ] Indy4 (Steam/Windows)
• [ ] Indy4 (Steam/macOS)
• [ ] Sam & Max (Steam/Windows)
• [ ] Sam & Max (Steam/macOS)
• [ ] The Dig (Steam/Windows)
• [ ] The Dig (Steam/macOS)