Provide offline install option like AppImage

[AHeinlein]

While SpeechNote is intended for "Offline use, no Internet connection required", Installation without Internet seems to be quite difficult. I have encountered multiple issues while trying this:

1. The preferred installation method seems to be flatpak. While flatpak knows an offline-install mode (https://docs.flatpak.org/en/latest/usb-drives.html), with which you can download a flatpak image and all depencencies to a USB drive, it is not straightforward.
2. I was able to build a debian package on an internet connected system. I had to modify the script and the debian control file, since they are missing quite some dependencies, but it worked. This, too, is not very straightforward.
3. After finally managing to install SpeechNote on an offline system, I couldn't find a way to download a model and get it working on the other machine - see #288

I'd really appreciate if there was an offline installable format like AppImage which you can just download, move to the other machine and use it there.

[Ivan2getdmodelz]

I was able to create a flatpak image on a USB. As you say, it was not straightforward. One thing I don't know how to resolve is including the Nvidia.addon in the flatpak. I've even tried to create that separately in using the same method, and it says it's not allowed. Did you, or has anyone, try to include the Nvidia.addon for GPU support? Additionally, the same question applies for some of the additional components, when using flatpak create-usb, it seems that it skipped some portions of the applications or runtimes, so in the offline machine, portions of the GUI (i.e. the top bar with minimize, maximize, and close) weren't included, and I am unable to move the Speech Note window around when open and running.