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
`yii\mongodb\log\MongoDbTarget` log target added
Fixes #4310: code cleanup
Fixes #4295: reworked message extraction for PO files
gii: fixed wrong composer.json template

reverts 45e4973ac80d4291dbc5cf321a088457b295d361
improved docs about goBack()

fixes #4343
Fixes #4331: `yii\helpers\Url` now uses `UrlManager` to determine base URL when generating URLs
Fixed test break.