Revert "core: add support for translucent volume panel"

This reverts commit 18c19fefda115bbec2a13a1edb7b2fa030aa0d0f.
Revert "Volume panel enhancements (position, color)"

This reverts commit 2d64b5adae3d10a27c592c3f64975662c7c677d3.
VolumePanel: Rework design on top of Hover

Signed-off-by: David L.-W. <xD_e-mail@gmx.de>

Conflicts: