Add option to follow authors - Make Lists books-only

Currently, you can add authors to lists (which doesn't work good to me anyway) and the only thing you can do with books is tag them but as something global which remains only on the web page of that book. In my opinion, it would be better if you could follow authors - and get some kind of notification when there's a new work - and add books to certain lists. Imagine you add an author who's general work is politics, but one time they decided to make a comic, that would also go into your "Politics" list even though it may not be related.

### Describe the problem that you'd like solved
I want an option to follow authors (and get notified, if possible) and another option to add books to lists.

### Proposal & Constraints
GoodReads, the proprietary web site where you can rate books and some other stuff, has this system, I really hate how they operate in a humanist level, but their structure is really good and I think there are some stuff that could be used from them. You can create a ton of lists and add a book to multiple of them.

### Additional context
I guess I could upload a screenshot of GoodReads, if someone thinks is necessary.

### Stakeholders