Book Editor Improvements

Book editing is fairly clunky. Let's fix that.

Changes that would not require data conversion:

• Add two buttons to insert a blank page before and after the current page, and a Remove Page button with a confirmation dialog.
• Add CTRL+Home and CTRL+End hotkey support to move the cursor to the beginning or end of the current page, similar to text editors such as Notepad++.
• Add CTRL+Left and CTRL+Right hotkey support to move the cursor from word to word.
• Add a button to toggle between 1-page or 2-page display, where 2-page would show two pages side-by-side. There would be a gap separating the two, odd pages would be on the left, and even pages on the right. This would allow for more complex books, such as a potion brewing guide. If considering data conversion, this tag could be saved with the item.
• Add a jump-to-page button, maybe by clicking the existing page number, where a page number could be entered.

Changes which could require data conversion:

• Save the previously opened page of a book, maybe reset when a different Player opens it.
• Save the time and date when a book is signed and display it, possibly in the tooltip. This couldn't be added to existing books; maybe it would display date signed: unknown. This would add a bit more permanence and novelty to books.

I stuck to self-contained changes which would not require significant changes to the books because I enjoy the simplicity of books written in survival. I don't see a need for, say, hovered tooltips or formatted text.