This PR enhances the CORS middleware usage by allowing for the headers
to be configured in `app.ini`.
Fixes#21746
Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: John Olheiser <john.olheiser@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>