Restructuring builds

[pjb7687]

Currently, we have two types of build on Linux/macOS: full and mini
And on Windows: full-msmpi, full, and mini

I think we can restructure this.

Firstly I think the name mini is not intuitive. From the previous discussion (#902), I was able to understand the main purpose to have mini build is for headless HPCs (since it targets HPCs, it makes sense to enable MPI with this).

But then, I think that it is too much to disable everything with mini builds. For example, plplot can work without GUI, and this can be used to plot to files... In principle, I think we can keep everything without wxWidgets?

Also, I suggest changing the name mini to something more intuitive, more clear it is targeting HPCs. How about headless? Also rather than full, I would say something like standard. I am open to any other name suggestions too.

My suggestion:

1. headless: we just get rid of wxWidgets, and keep everything else + MPI
2. standard: everything without MPI

[slayoo]

related: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=753618
(wishlist item for a gdl-nox pacage)