Add XDG autostart support

[rizalmart]

Please add a user option to start caprine automatically in minimized state upon system start

[mquevill]

There is an option to launch minimized under File > Caprine Settings > Launch Minimized.

As for running with system startup, that is not handled by Electron. You would need to look into the specifics for your operating system/desktop environment. (For example, in Linux Mint with Cinnamon, there is a "Startup Applications" menu where you could select Caprine to run during startup.)