Add composer.json and use composer to install all the required libraries and perform a clean up.

It looks like this project has stalled ...

The closest thing to Elementor in Drupal is probably the Mercury Editor → . You can try a fully functional demo by installing the test module, see my README MR.

See also this presentation from Nov 6, 2023: Mercury Editor: Easy-to-Use, Drag-and-Drop Content Editing for Drupal.

Looks like there's some activity again on a 3.x branch.

The problem with composer install is that the elementor package name is incorrect - it should be elementor/elementor.

To get around this before the fix is committed, add this to your composer.json:

"repositories": [
        {
            "type":"package",
            "package": {
                "name": "elementor/elementor",
                "version": "3.29.0",
                "source": {
                    "url": "https://github.com/elementor/elementor.git",
                    "type": "git",
                    "reference": "main"
                }
            }
        }
    ]