Merge kkrnano-constaint-bfields in, first version that compiles

.gitlab-ci.yml

CHANGELOG.md

ElementDataBase/Bi83.pot

cmake/compiler_config.txt

cmake/source_list_KKRhost.txt

cmake/source_list_common.txt

docs/settings_ford.md

source/KKRhost/bzkint0.f90

source/KKRhost/interpolate_poten.f90

source/KKRhost/kkrmat01.F90

source/KKRhost/main0.F90

source/KKRhost/main1c.F90

source/KKRhost/mixnocospin.f90

source/KKRhost/renorm_lly.f90

source/KKRhost/rhooutnew.F90

source/KKRhost/rhovalnew.F90

source/KKRhost/rinput13.F90

source/KKRhost/tmat_newsolver.F90

source/KKRhost/wunfiles.F90

source/KKRimp/kkrflex.F90