Web Inspector: [Settings] Add "storage" parameter to WebInspector.Setting
https://bugs.webkit.org/show_bug.cgi?id=112667

Reviewed by Pavel Feldman.

New parameter will allow more options on how long setting will persist.
Possible options are: localStorage, sessionStorage and no-storage.

Additional change: use delete instead of .removeItem to make it possible
use any object as storage.

* inspector/front-end/Settings.js:
Added "storage" parameter and used is instead of "window.localStorage".


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146317 268f45cc-cd09-0410-ab3c-d52691b4dbfc