v1: Add rounded corners effects to all windows

Should be works in Gnome 40 / 41 / 42

• Custom border radius and clip paddings for windows
• Black list for applications which draw window decoration itself
• Custom shadow for rounded corners windows
• Custom border-width and border-color for rounded corners windows
• Skip libadwaita / libhandy application
• Perferences pages built by libhandy
• Menu Item in background to open preferences pages.

Special thanks to @Aleksanaa help test bugs of this extensions.

Context menu item in background:

Preferences pages

Edit shadow for rounded corners window