Add a 2nd theme ― mdBook

[srid]

Add a new template layout that mimics the mdBook look.

And then test it in flake-parts/community.flake.parts#7

[srid]

Context:

cardano-foundation/cardano-wallet#4006 (comment)

Interesting. Is there a particular set of features Emanote could have supported to obviate this change?

The main reason for switching was actually that I find the default mdbook theme to be visually more appealing:

• The theme reserves almost all space for the text (e.g. hides by the navigation bar by default), making the text easier to read.
• The navigation bar is more clear, with section numbers and better scrolling behavior.

That's about it, usability of the executable or configuration did not really factor into the decision. 🤔