Add a category "contains Fortran"

[certik]

We should add a new category:

• Codes that contain some Fortran code, but Fortran is not the primary development language (either has never been, or is not anymore) as judged from the latest commits in the last few years. It does not matter in terms of lines if the Fortran code is a majority or minority.

What this category will show is what projects depend on Fortran, even if only as "clients". All those projects will benefit from any improvement we will do for the Fortran ecosystem, even if indirectly.

Here I found libraries that fit exactly into this category:

• https://github.com/scipy/scipy
• https://github.com/xianyi/OpenBLAS

And I think many of these fit there also (they all have Fortran code inside, but I suspect Fortran is not the primary development language):

• https://github.com/keflavich/plfit
• https://github.com/kthyng/tracpy
• https://github.com/dfm/python-fsps
• https://github.com/sonofeft/RocketCEA
• https://github.com/pvthinker/Fluid2d
• https://github.com/stfc/PSyclone
• https://github.com/mancellin/capytaine

I am sure there are many more such projects.