ifort build all

[bblay]

Finishing touch: I think we just need to find the type specification for ifort, like the ones we have for gfrotran, to avoid the type mismatch errors. I think this will let us build UM and LFRic ATM with ifort.

This is really an issue with the nightly run configs, not Fab itself.

done:

• replaced the hard-coded gfortran -J flag
• both gfortran and ifort are tested regularly in #160