Change colors for links and hyperref (#206)

* Change colors for links and hyperref

This is less in your face than what we previously had.

Discussion in :
https://github.com/hendricius/the-sourdough-framework/discussions/201

There might be ways to make that better (not in your face and clickable
?)
https://tex.stackexchange.com/questions/555663/create-a-table-of-contents-with-links-in-all-text-and-different-colours-for-sect

* Remove colors for links in To*

As per @hendricius input

book/book.tex

@@ -13,8 +13,10 @@
 \titlepage
 
 \frontmatter
-% \tableofcontents
+{%
+\hypersetup{hidelinks}
 \ifdefined\HCode\else\tableofcontents\fi
+}
 
 \input{intro/foreword}
 \input{intro/preface}
@@ -61,8 +63,11 @@
 
 \backmatter
 \printbibliography
+{%
+\hypersetup{hidelinks}
 \listofflowcharts
 \listoftables
 \listoffigures
+}
 
 \end{document}