v4.0.0: docs(readme): rewrite for Drupal 11 and document ddev setup

Replaces the plain text README with a README.md that says what the module
actually does, lists the core dependencies and the media types and image
style the settings form assumes, and shows the twig usage.

Adds a development section for the ddev project, including the phpstan
config path that has to be passed by hand, and records the known issues
found while upgrading.

Fix D10 Deprecated funciton file_create_url

Error: Call to undefined function file_create_url() in _custom_design_preprocess_var() (line 27 of modules/contrib/custom_design/custom_design.module).

D10 Compatibility

Updated info.yml file to support D10

v3.0.1

Update custom_design.info.yml

1.0.8: Merge pull request #1 from mikecrittenden/patch-1

Remove $request param from buildForm()