Ensure all scripts are desktop agnostic

[W-Floyd]

Specifically, KDE and Gnome are my targets, though contributions are welcome for any others.

[W-Floyd]

List of explicitly DE dependent scripts.

• monitor.sh - Setting color temperature - GNOME only.
• bedtime.sh - Not applicable, this is a GNOME extension.
• theme.sh - Setting light/dark mode, plus terminal color change (this part should be retired) - GNOME only.
• screen.sh - Getting screenshot - GNOME only
• theme-nightthemeswitcher.sh - Not applicable, this is a GNOME extension.
• screenlock.sh - Locking/unlocking and checking screen lock state - 🎉 Supports KDE and GNOME!