Adding CORS filter to allow Cross origin resource Sharing
Adding enhancement CORS
Move methods
Fix changelog
Merge branch 'master' into feature/CORS
Allow the user to override the request like in RateLimiter
Fix multiple headers management in Access-Control-Request-Headers
Allow the user to remove field by nulling it's value. Usefull for Access-Control-Max-Age
Remove static functions
Adding CORS documentation
Fix link
Move CORS documentation from REST to Structure
Fix unused var
Fixes #3443: Fixed `yii\bootstrap\Nav` and `yii\bootstrap\Dropdown` were generating wrong ids for submenus
Passed "encodeLabels" to Dropdown recursive call
Better fix for #3443
Even better fix for #3443
Merge pull request #4193 from pgaultier/feature/CORS

CORS Filter
Basic edits
minor doc fix. [skip ci]