Merge branch 'data_model' into 'devel'

.gitlab-ci.yml

LICENSE

docs/guide/libbbfdm_GRE.md

docs/guide/libbbfdm_IP_Interface.md

docs/guide/network_depoyment_scenarios.md

gitlab-ci/compile.sh

gitlab-ci/shared.sh

src/Makefile

src/common.c

src/common.h

src/gre.c

src/gre.h

src/interfacestack.c

src/interfacestack.h

src/ip.c

src/ip.h

src/net_plugin.c

src/ppp.c

src/ppp.h

src/routeradvertisement.c