Implement browser action for toggling redirection

[vhfmag]

This PR implements the feature suggested in #14: a toolbar button that enables/disables redirection on toggle. This adds a new permission request (storage, for persisting this preference) and doesn't redirect immediately in case a user enables redirection while in a youtube domain, as this would require either:

• Duplicating the redirection code in background and makehook files
• Using a bundler to be able to reuse a redirect function
• Import html files instead of js ones for both content script and background, so that they're included as ES modules (<script type="module" src="background.js">) so that they can use import (to be fair, I'm not even sure content scripts can be added through HTML)

Thanks for the good work with this extension :)

Closes #14

[metiis]

Sorry for the late response on this, I kinda forgot about this. Unfortunately this is already being implemented with #19, thanks a lot for your work with this though :)