Port PDF generation to Hugo

[MuhammadAashirAslam]

Ports the documentation PDF workflow from Jekyll to Hugo and Prince. Adds Hugo PDF configuration, templates, sidebar-driven contents, local print assets, and an updated pdf-docs.sh generator while removing obsolete Jekyll PDF files.

Generated PDF: https://drive.google.com/file/d/1zuifXDzyl4Xiy0xE8GPifccP-K9mOIsT/view?usp=sharing

[MakisH]

Some comments on the attached PDF:

• In the ToC:
  • Ideally, keep the section and page number on the same line, if it fits.
  • The page number has a serif font, the section a sans-serif font (use the sans-serif for both).
• Internal links should point to the PDF. They currently point to 127.0.0.1.
• In dependencies overview (page 34), there is a no-icon.
• In the Roadmap (page 20), the button "click here" should be replaced by the text (unreleased changes).
• Would there be a command to hard-code to start a new page?
• In the Distribution (page 86), the DOI/DaRUS button is centered, the "external link" icon is on another line. Also in page 129.
• Page 99: table headings with code snippets have a wrong color.
• Page 168: no distinction between inline math and math blocks.
• Page 173: table width.
• Page 194: bloken tables.
• Page 273: the image could be smaller.
• Page 297: the tabs have some issues (numbers not shown, active tab name not readable). There are more issues on the page.