Utils/QmlJS: Move contents of utils/json.{h,cpp} to qmljs

This is a special version of JSON only used in the QmlJSEditor,
demote it accordingly.

Change-Id: Id21ea16c022fb8554d87e9ba90c3494978e4cd80
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/qmljseditor/qmljssemanticinfoupdater.cpp

@@ -14,8 +14,6 @@
 
 #include <coreplugin/icore.h>
 
-#include <utils/json.h>
-
 namespace QmlJSEditor {
 namespace Internal {
 
@@ -97,7 +95,7 @@ QmlJSTools::SemanticInfo SemanticInfoUpdater::makeNewSemanticInfo(const QmlJS::D
     semanticInfo.setRootScopeChain(QSharedPointer<const ScopeChain>(scopeChain));
 
     if (doc->language() == Dialect::Json) {
-        Utils::JsonSchema *schema = QmlJSEditorPlugin::jsonManager()->schemaForFile(
+        JsonSchema *schema = QmlJSEditorPlugin::jsonManager()->schemaForFile(
             doc->fileName().toString());
         if (schema) {
             JsonCheck jsonChecker(doc);