feature: Wallpaper app support for per-display and cropping settings

[hurlbutt]

Description

This pull request enhances the Wallpaper Quickshell app to provide additional advanced settings:

• Setting wallpaper for single outputs (default is all outputs)
• Setting position of wallpaper image in screen (in case cropping is needed) in support of new feature of awww 0.12.1 (default is centered)
• Disabling using new wallpaper for matugen and other ML4W theming changes (enabled by default)

Changes

• Updated ml4w-autostart to start awww-daemon and to only call ml4w-wallpaper when there exists no awww cache (otherwise let awww handle restoring wallpapers from its own cache)
• Updated ml4w-wallpaper to support additional parameters:
  • --skip-wallpaper Will skip setting the wallpaper with awww
  • --skip-theming Will skip updating OS themes based on new wallpaper.
  • --skip Alias for "--skip-wallpaper".
  • --monitor Specify which input to apply wallpaper change (default applies to all outputs)
  • --crop-gravity Specify where to anchor wallpaper image in case cropping is needed (values from 'awww img --crop-gravity; default is center)
• Refactored ml4w-wallpaper to consolidate awww/wallpaper functions and theming functions together
• Refactored WallpaperWindow.qml to componentize ComboBox and CheckBox styling and applied throughout the app
• Added advanced option to choose specific output to apply wallpaper change
• Added advanced option to choose where to position wallpaper image in monitor in case cropping is needed
• Added advanced option to not apply matugen and ML4W theming changes as a consequence of changing wallpaper

How Has This Been Tested?

• Tested on Arch Linux/Based Distro.
• Tested on Fedora Linux/Based Distro.
• Tested on openSuse.

Checklist

Please ensure your pull request meets the following requirements:

• My code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• My changes do not introduce new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• I have made corresponding changes to the documentation
• New and existing unit tests pass locally with my changes.

Screenshots

Additional Notes

• The wallpaper position functionality requires awww 0.12.1 to function. ml4w-wallpaper checks for the awww version, and it will drop the flag for cropping if the version isn't at least 0.12.1.

[mylinuxforwork]

This is great. But cannot add it now to 2.13.0. But will test it immediately after the release foe 2.13.1

[hurlbutt]

@mylinuxforwork - Sounds good. Also, feel free to prescribe any styling changes to the checkbox component. I tried to use the theming attributes from the other elements to style the box, but I'm not tied to any of the implementation details and would welcome feedback.