ios cookie rewrite using mozilla docCookies

Rewrite of ios cookie back-end using [mozilla doccookies](https://developer.mozilla.org/en-US/docs/Web/API/document.cookie#A_little_framework.3A_a_complete_cookies_reader.2Fwriter_with_full_unicode_support) as a base (but calling executeAtom instead of injecting). 

@jlipps @0x1mason can you have a look.