Refactor CORS handler (#28587)

The CORS code has been unmaintained for long time, and the behavior is
not correct.

This PR tries to improve it. The key point is written as comment in
code. And add more tests.

Fix #28515
Fix #27642
Fix #17098

custom/conf/app.example.ini

@@ -1158,15 +1158,9 @@ LEVEL = Info
 ;; enable cors headers (disabled by default)
 ;ENABLED = false
 ;;
-;; scheme of allowed requests
-;SCHEME = http
-;;
-;; list of requesting domains that are allowed
+;; list of requesting origins that are allowed, eg: "https://*.example.com"
 ;ALLOW_DOMAIN = *
 ;;
-;; allow subdomains of headers listed above to request
-;ALLOW_SUBDOMAIN = false
-;;
 ;; list of methods allowed to request
 ;METHODS = GET,HEAD,POST,PUT,PATCH,DELETE,OPTIONS
 ;;