Also switch to argparse for correct parsing of arguments and help

Also update to \inline.

Also change paragraph to subsubsection.

Usage notes are found in the module docstring.

Using matrix to run several jobs in parallel seems to
make it complicated to link to build
artifacts directly. Thus, I added a link to the jobs page.

Because the GitLab CI can’t run apt-get at the moment, the font must be
embedded into the project instead of installed in the container.
Also, a switch is added so that if a machine has the font installed, it
uses that version. This is needed because LuaLaTeX doesn’t like using
the project .ttf files on my machine. So this is a workaround for that.

The ubuntu/focal repository provides an old version of the markdown
package which doesn’t support the jekyllData and taskLists options.
Since they are not used at the moment, they are commented out.
Reactivating them would require setting up an additional apt repository.