Feature Request: Close/minimize to system tray (Windows)

[nathlrowe]

Add option to have application be minimized to the system tray instead of quitting completely.

My ideal is to be able to have a lightweight Proton Mail process running in the background, with an icon in the system tray, giving me notifications when a new email arrives or on calendar events. For example, I have my Discord app configured to minimize to tray when I click "X", instead of closing completely. This clears space on my taskbar, while keeping me notified of Discord messages.

I would also want "Start Proton Mail on startup" and "Start Proton Mail minimized to tray" options as well.

[Zie0]

I believe this issue is a duplicate of #10