This was based on the similar section in the hedgedoc. I dropped the bit
about grapevine users getting banned from the conduwuit rooms cause we
haven't heard about that happening for a while and the original case was
pretty unclear.
The maintainers had a discussion internally and decided it's unlikely
that we'll have the capacity to try to do a rewrite, which was the
original reason for the suffix's presence. So, now can get rid of it.
This adds some new tools in CI for lint the book and also sets up
automated deployment to GitLab Pages. Also adds a readme that suggests
reading the book, since that's where all the information will be.
