[NEW, CHANGE] Crop marks for PDF/LaTeX output

[Rob Beezer]

You may have seen "crop marks" on proofs of your publications coming back from
publishers. They are also useful if your publisher expects you to provide
"camera-ready copy" and your book size is smaller than your printer paper.

These were possible, but not very flexible, as part of a very old "author tools"
option for LaTeX/PDF output. I've split them out as their own feature, elected
via your publication file.

Subsection 44.3.4: LATEX Page Shape Options
https://pretextbook.org/doc/guide/html/publication-file-latex.html#latex-page-options

Section 30.6: Page Shape
https://pretextbook.org/doc/guide/html/page-shape.html

Rob