feat: new cookie store

[kettanaito]

Implements a new CookieStore that:

• Respects cookie domain and the response issuer origin;
• Respects cookie path and the given request pathname (when returning relevant request cookies);
• Has no persistence (use document.cookie and CookieStore.parse() in the browser instead).
• Gets rid of the barrel export in index.ts.

Motivation

I feel like some of the functionality of this library is no longer relevant in MSW 2.0. I also feel like some of its functionality was a bit incorrect, like never taking the cookie's path into account in the .get() method. I also can't remember most of the intentions behind some of the methods.