Add AppImage installation method

[hwittenborn]

No description provided.

[jacobgonzales20]

Would be great for portability

[hwittenborn]

I want to add this, but AppImage's have shown to be quite annoying to package for (at least for me), especially when older libc versions are needed.

There was a point where AppImages were implemented, but library issues always caused problems so it got removed. I might look into it again soon, I'll send a message when I get anything going.

[dzek69]

Perhaps you can prepare a docker image to build AppImages if that requires some dependencies messing up with your standard OS install

[hwittenborn]

A main issue for me was using some simple tooling - I don't want to have to generate the AppDir manually, so I tried using appimage-builder, but it never worked with Rust binaries as I reported here: AppImageCrafters/appimage-builder#284. I've yet to find any other tooling that works as simply as appimage-builder does though, so I've just stopped working on it.

If you know of any tools to get the job done, feel free to send them over though.

[hwittenborn]

I just did some testing with a test GTK3 application, and it looks like cargo-appimage does the job perfectly.

It'll probably have to wait until #84 is done so that everything can be in one application, but after that I definitely want to give this a look.

[hwittenborn]

I did some more testing, and cargo-appimage is having some limitations that break backwards compatibility. It also lays out files in a way that I don't necessarily like.

I could fix the issues in cargo-appimage (I already know how), but I've decided I'm just going to make a new tool that makes it easier to make AppImages for any kind of package, not just limited to Rust packages. Outside of cargo-appimage I haven't found anything that's user friendly enough for my desires, so I'm just going to start getting something going myself. I've figured out how to make everything work doing manual intervention, so now I've just got to make it all happen automatically.

I've got some fixes for some other issues locally, I've just got to get this going and then it'll all be good to go.

[hwittenborn]

I just found out about FlatImage the other day, and it looks like it'll solve my needs pretty perfectly. There doesn't seem to be any issues with dependencies when using it - I did some testing with various apps and they all just worked, without any manual intervention on my part.

At the least, the FlatImage could be put inside of an AppImage for people who still want to use something that resembles an AppImage.