Undo history for creating and deleting scripts

[anthonyec]

Changes

• Add undo system that stores closures for undo steps. Might be better to use Redux but this works ok for now.
• Add ability to show toast messages
• Create useBrowserBookmarks hook for interacting with chrome.bookmarks. This is different to how it was done, using actions and dependency injection. It's easier doing it this way, but I will see how it goes.
• Hard code popup home screen width because toast will change it willy nilly

Notes

• Holding down Command + Z to undo can be slow. This is because I don't properly queue the undos, they uses promises and I keep a reference to a bool to know when each undo is being processed. Would be nice to fix this so it's super fast