monaco: support non editable mode

by setting "readOnly" to true.
Monaco also supports applying its style to a <pre> element (like on
https://microsoft.github.io/monaco-editor/playground.html#creating-the-editor-syntax-highlighting-for-html-elements
) but it would be a too big architecture change, a readOnly editor is
enough.

bt5/erp5_monaco_editor/SkinTemplateItem/portal_skins/erp5_monaco_editor/monaco-editor.gadget.js.js

@@ -171,6 +171,8 @@
             .push(addExtraLibrary('./monaco-renderjs.d.ts', 'renderjs'))
             .push(addExtraLibrary('./monaco-jio.d.ts', 'jio'));
         }
+      if (modification_dict.hasOwnProperty('editable')){
+        gadget.editor.updateOptions({readOnly: !this.state.editable});
       }
       return queue;
     })

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/gadget_editor.js.js

@@ -112,6 +112,7 @@ lockGadgetInQueue, unlockGadgetInQueue, unlockGadgetInFailedQueue*/
              (editor_dict.hasOwnProperty(gadget.state.editor))) ||
             (!gadget.state.editable && gadget.state.editor === 'fck_editor') ||
             (!gadget.state.editable && gadget.state.editor === 'jsmd_editor') ||
+            (!gadget.state.editable && gadget.state.editor === 'monaco') ||
             (gadget.state.editor === 'pdf')) {
           queue
             .push(function () {
@@ -143,6 +144,7 @@ lockGadgetInQueue, unlockGadgetInQueue, unlockGadgetInFailedQueue*/
              (editor_dict.hasOwnProperty(gadget.state.editor))) ||
             (!gadget.state.editable && gadget.state.editor === 'fck_editor') ||
             (!gadget.state.editable && gadget.state.editor === 'jsmd_editor') ||
+            (!gadget.state.editable && gadget.state.editor === 'monaco') ||
             (gadget.state.editor === 'pdf')) {
         queue
           .push(function () {