style: Stylesheet updates for GNOME 42

style: Stylesheet updates for GNOME 42

- updated switch assets
 - new high contrast assets
- use non-hardcoded bg color for dash
- updated palette colors
 - add missing color definitions to hc
- increase radii of many elements
- update search entry style
- align icon better in search entry
- restyle panel popovers without arrow and add drop shadow
- used theme colors in panel
- fix some things with popover labels
- new slider style
- some light variant fixes
- fixes to the calendar popover
 - day with event styles
 - better calendar-today.svg and dark variant
 - shorten calendary weekday header
 - saner padding
- overhaul popover menu style
- minor fixes to app grid and alt-tab switch
- updated looking glass styles
- nm-dialog adjustments
- search results adjustments
- expand out panel button hover styles
- button drawing adjustments
- adjust notifications area
- update on-screen keyboard style
 - better keyboard symbolic icon assets
 - change keyboard symbolic icons to 24px
 - improved keyboard style
 - gave the keyboard word suggestions some styles
- less obnoxious saner media control buttons
- cleaned up the css for the dash
- reworked the alt-tab switcher style
- sync style on workspace switcher
- adjusted dialog button style drawing
- popover submenu redrawing adjustement

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2104>