Linux: Build in one-dir mode and use AppImage tools #341
Description
Instead of using PyInstaller's onefile mode (self-extracting-executable) on Linux, we should build in one-dir.
This has the following advantages:
- Use a standard "portable single executable" on Linux
- Ship with an icon (Generate a Desktop icon on Linux #274) and allow users to use AppIamge-related tooling (like auto-registration as apps)
- Better UPX compression