KeepassXC as a service

[samarsault]

Summary

Add an option to run the KeepassXC as a background service, i.e. something similar to macOS menubar application

Examples

Docker runs in the background, as a service.

Context

When using the KeepassXC-Browser extension, the database gets locked automatically after sometime. Also, the window is an extra clutter on the screen.
I understand that having the auto-locking feature is important for security, but I think a user should be allowed to compromise it for a significant usability improvement.

[phoerious]

Duplicate of #1334.