new: Write a book from text file on disk

[mvrozanti]

Add the ability to write a book given a text file on disk.

When activated, the mod would look for a book in the main inventory if it's not on the hotbar and put it in the hotbar. Once in the hotbar switch active slot to the one the book is in. Open book. Input text file data. Optionally sign book.

A problem that could arise is how to split text between pages so as to not cut a word between two pages. When this happens, limit former page to the last space and break page at the space character's index.