mdoc by default

[juanpedromoreno]

tut has been deprecated and the recommendation is to switch to mdoc.

This PR makes mdoc the default compiling tool, although users could still use WithTut if needed.

[calvellido]

If you want to, we can take the rains and have a look at those failing tests on the road to 1.0.0

[juanpedromoreno]

Thanks @calvellido , I think I've fixed them in 423da27 (at least in my laptop :D )

[calvellido]

Great! 👏 @AntonioMateoGomez, when you start outlining release notes, and blog post, please bear in mind and point out that this a breaking change (in the sense that even if easy, it will require user intervention when updating sbt-microsites) for 1.0.0.

Thanks!