WIP: Erp5 text editor migration

This MR contains work for the new OfficeJS approach and migration of text editor app.

For more details, please check: https://www.erp5.com/NXD-Work.Description.Roque.Porchetto

For full commit history and discussion, please check the previous MR: https://lab.nexedi.com/nexedi/erp5/merge_requests/833