but not working properly yet

Otherwise some symmetries are falsely flagges as anti-unitary
which leads to wrong results (symmetry matrices dsymll are
treated differently for unitary and anti-unitary transformations).

$ mpif90 --version
GNU Fortran (Debian 10.2.1-6) 10.2.1 20210110

$ ompi_info | head -n4
                 Package: Debian OpenMPI
                Open MPI: 4.1.0
  Open MPI repo revision: v4.1.0
   Open MPI release date: Dec 18, 2020

- add external libraries 'symlib' and 'sorting' from github
- write inputFS template from KKRhost
- add write_Pkkr_bands input for new bands.x interface
- add functionality to use bands module inside KKRhost with refinement (work in process)
- prepare calc_bands_pkkr input (work in progress)

Partial norm

See merge request kkr/jukkr!6

Update tests and activate CI tests for KKRimp

See merge request kkr/jukkr!7