p7zip requirement can't be satisfied by official 7zip

[JohnTheCoolingFan]

Original issue: an-anime-team/sleepy-launcher#1

I have a Gentoo system, which provides non-conflicting p7zip and 7zip (official linux version). I have 7zz aliased to 7z, but it doesn't recognize it. I couldn't complete the initial setup without installing app-arch/p7zip.

Furthermore, if the sdk uses 7zip as just a universal archive tool, I think that could be changed to atool, which is basically a wrapper around other specialized archive tools such as unzip. So unless you need to work with 7z archives, 7zip isn't needed.

I do realize that this would mean changing quite a bit of the crate and would change the host package dependency list. I would like to offer my help with that, I know rust enough to contribute. And I am open to discussion on this one.