Quality of life improvements to the new editor

[anna-geller]

Feature description

• Right-click on the tab menu: "Close all tabs" + "Close other tabs" + "Close tabs to the right"
• Add horizontal scroll bar when the file is too long https://share.descript.com/view/lMp67IZsjUk
• Right-click action to:
  • create a new file with extension (e.g. myscript.py) or folder

[MilosPaunovic]

Adding two remaining tasks from #3694

• when using subflows, allow opening a subflow in a new editor Add autocompletion to subflows #2473
• Add support for bulk-delete by holding a Shift-key -- when you select one file or folder, click on the Shift key and select other files, this should allow to bulk-select and bulk-delete multiple files or folders
  

[wrussell1999]

Along with bulk-delete, would it be possible to add bulk-move files by shift click and then drag to a folder?