Theme consistency overhaul:

- Add surface shift option, start from surface by default (previously
  was surfaceContainer). Old colors can be attained by changing it back
to "container" in theme colors
- Remove borders on surface elements, mostly
- Fix popup distances
- Use surfaceContainer/sch by default on widgets

Modules/ControlCenter/Widgets/InputAudioSliderRow.qml

@@ -68,7 +68,7 @@ Row {
         unit: "%"
         valueOverride: actualVolumePercent
         thumbOutlineColor: Theme.surfaceContainer
-        trackColor: root.sliderTrackColor.a > 0 ? root.sliderTrackColor : Qt.rgba(Theme.surfaceVariant.r, Theme.surfaceVariant.g, Theme.surfaceVariant.b, Theme.getContentBackgroundAlpha() * 0.60)
+        trackColor: root.sliderTrackColor.a > 0 ? root.sliderTrackColor : Theme.surfaceContainerHigh
         onSliderValueChanged: function(newValue) {
             if (defaultSource) {
                 defaultSource.audio.volume = newValue / 100.0