Remove qml-debug configure flag and feature

The feature belongs to qtdeclarative and will be added there.

Change-Id: I2faf89f6caf841958e60efed8ff3882e530f0720
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

config_help.txt

@@ -201,7 +201,6 @@ Component selection:
   -dbus-runtime ........ Build Qt D-Bus and dynamically load libdbus-1 [no]
   -accessibility ....... Enable accessibility support [yes]
                          Note: Disabling accessibility is not recommended.
-  -qml-debug ........... Enable QML debugging support [yes]
 
 Qt comes with bundled copies of some 3rd party libraries. These are used
 by default if auto-detection of the respective system library fails.

configure.json

@@ -102,7 +102,6 @@
             "platform": "string",
             "plugin-manifests": "boolean",
             "profile": "boolean",
-            "qml-debug": "boolean",
             "qreal": "string",
             "qtlibinfix": { "type": "string", "name": "qt_libinfix" },
             "qtnamespace": { "type": "string", "name": "qt_namespace" },
@@ -1235,13 +1234,6 @@
             "condition": "libs.libudev",
             "output": [ "privateFeature" ]
         },
-        "qml-debug": {
-            "label": "QML debugging",
-            "output": [
-                "privateFeature",
-                { "type": "publicQtConfig", "negative": true }
-            ]
-        },
         "compile_examples": {
             "label": "Compile examples",
             "output": [ "privateConfig" ]
@@ -1454,7 +1446,6 @@ Configure with '-qreal float' to create a build that is binary-compatible with 5
             "section": "Support enabled for",
             "entries": [
                 "pkg-config",
-                "qml-debug",
                 "libudev",
                 "system-zlib"
             ]