Remove features related to desktop overlay translation

The feature was killed by Valve and is not likely to come back.

src/res/qml/desktop_overlay_page/translation_back_forwards/SteamDesktopTranslationBackForwards.qml

@@ -1,22 +0,0 @@
-import QtQuick 2.7
-import QtQuick.Controls 2.0
-import QtQuick.Layouts 1.3
-import ovras.advsettings 1.0
-import "../../common"
-
-FullWidthSliderBox {
-    headerMessage: "Forwards/Backwards Translation"
-
-    lowerLimit: -4.0
-    upperLimit: 4.0
-    sliderStepSize: 0.10
-    kbUID: 603
-
-    function onValueChanged(value) {
-        DesktopOverlay.forwardsMovement = value
-        sliderText = value.toFixed(2)
-    }
-    function onComponentComplete() {
-        sliderValue = DesktopOverlay.forwardsMovement
-    }
-}

src/res/qml/desktop_overlay_page/translation_left_right/SteamDesktopTranslationLeftRight.qml

@@ -1,22 +0,0 @@
-import QtQuick 2.7
-import QtQuick.Controls 2.0
-import QtQuick.Layouts 1.3
-import ovras.advsettings 1.0
-import "../../common"
-
-FullWidthSliderBox {
-    headerMessage: "Left/Right Translation"
-
-    lowerLimit: -4.0
-    upperLimit: 4.0
-    sliderStepSize: 0.10
-    kbUID: 604
-
-    function onValueChanged(value) {
-        DesktopOverlay.rightMovement = value
-        sliderText = value.toFixed(2)
-    }
-    function onComponentComplete() {
-        sliderValue = DesktopOverlay.rightMovement
-    }
-}

src/res/qml/desktop_overlay_page/translation_up_down/SteamDesktopTranslationUpDown.qml

@@ -1,22 +0,0 @@
-import QtQuick 2.7
-import QtQuick.Controls 2.0
-import QtQuick.Layouts 1.3
-import ovras.advsettings 1.0
-import "../../common"
-
-FullWidthSliderBox {
-    headerMessage: "Up/Down Translation"
-
-    lowerLimit: -4.0
-    upperLimit: 4.0
-    sliderStepSize: 0.10
-    kbUID: 602
-
-    function onValueChanged(value) {
-        DesktopOverlay.height = value
-        sliderText = value.toFixed(2)
-    }
-    function onComponentComplete() {
-        sliderValue = DesktopOverlay.height
-    }
-}