Follow up to the new Editor

[anna-geller]

Feature description

• Bring back autocompletion https://share.descript.com/view/qzSqX2OpPcB
• Remove the VS Code Editor sidebar (and everything related to VS Code)
• Import folder functionality not working in the new Editor -- the folder got imported 35 times #3687
• Topology view tries to take too much space 😄  #3686
• Revision history throws a TypeError: this.editor.onDidFocusEditorText is not a function #3691
• Auto-collapse the Namespace Files Editor sidebar -- it's cleaner and doesn't introduce extra complexity for users who don't use Namespace Files
  
• Add a slider allowing to resize the sidebar https://share.descript.com/view/UYwAYEnQrCL https://share.descript.com/view/oApRm9DKpcG
• Regression on the main slider https://share.descript.com/view/srOiMLzdQRZ on the editor-follow-up branch
• Reduce the width of the sidebar to provide enough space for the Editor and documentation
  
• Remove the Getting Started markdown file. We can now implement a better UX to guide people through the editor
  
• 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
  
• Remove mandatory file extension "Missing file extension", people could add file without

[brian-mulier-p]

• (maybe) add a placeholder value when there is no files created yet to show users it's not buggy

It wasn't needed before but since I removed the getting_started.md it looks weird to have an empty browser without saying anything idk WDYT @anna-geller ?

[anna-geller]

I would auto-collapse by default and make the expand icon more prominent (perhaps add a little color to it e.g. purple?)

[MilosPaunovic]

For now, added the placeholder value for the situation when there are no namespace files and also, the sidebar is collapsed by default, but the button is made more prominent.

And @brian-mulier-p removed the getting-started.md file in 9189cd6 yesterday.