Re-enable QmlProjectManager by default

Acting on user feedback.

This essentially reverts commit 7e8fb3a9e9,
but demotes the wizards from "Application" to "Project" and adds
a tooltip in the hope to make "accidental" use less likely.

Change-Id: I385bcfc5cdcb9bb3c36f9168a7fc6480f4fc5062
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@theqtcompany.com>
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

share/qtcreator/templates/wizards/projects/qmlproject/qtquickapplication/wizard.json

@@ -2,8 +2,8 @@
     "version": 1,
     "kind": "project",
     "id": "QA.QtQuickUi",
-    "category": "F.Application",
-    "trDescription": "Creates a Qt Quick 2 UI project.",
+    "category": "H.Project",
+    "trDescription": "Creates a Qt Quick 2 UI project with a QML entry point. To use it, you need to have a QML runtime environment such as qmlscene set up. Consider using a Qt Quick Application project instead.",
     "trDisplayName": "Qt Quick UI",
     "trDisplayCategory": "Application",
     "icon": "../../qmake/qtquickapplication/qml_wizard.png",

share/qtcreator/templates/wizards/projects/qmlproject/qtquickcontrolsapplication/wizard.json

@@ -2,8 +2,8 @@
     "version": 1,
     "kind": "project",
     "id": "QB.QtQuickControlsUi",
-    "category": "F.Application",
-    "trDescription": "Creates a Qt Quick 2 UI project using Qt Quick Controls.",
+    "category": "H.Project",
+    "trDescription": "Creates a Qt Quick 2 UI project using Qt Quick Controls with a QML entry point. To use it, you need to have a QML runtime environment such as qmlscene set up. Consider using a Qt Quick Controls Application project instead.",
     "trDisplayName": "Qt Quick Controls UI",
     "trDisplayCategory": "Application",
     "icon": "../../qmake/qtquickapplication/qml_wizard.png",

src/plugins/qmlprojectmanager/QmlProjectManager.json.in

@@ -2,7 +2,6 @@
     \"Name\" : \"QmlProjectManager\",
     \"Version\" : \"$$QTCREATOR_VERSION\",
     \"CompatVersion\" : \"$$QTCREATOR_COMPAT_VERSION\",
-    \"DisabledByDefault\" : true,
     \"Vendor\" : \"The Qt Company Ltd\",
     \"Copyright\" : \"(C) 2015 The Qt Company Ltd\",
     \"License\" : [ \"Commercial Usage\",