Feature request: CORS settings

[kaidesu]

Is your feature request related to a problem? Please describe.

Add ability to configure CORS settings through the control panel.

Feature request checklist

• This is a single feature (i.e. not a re-write of the entire CMS)
• The title starts with "Feature request: " and is followed by a clear feature name (Ex: Feature request: add konami code to control panel)
• I have searched for existing issues and to the best of my knowledge this is not a duplicate