A bit hacky: the ranap_ies_defs.h is generated together with the
ranap_encoder.c and ranap_decoder.c. See comments in src/Makefile.am and
include/osmocom/ranap/Makefile.am.
Do all remaining changes necessary for a working build.
Add Makefile.am files in include/... subdirs.
Remove noinst_HEADERS directives from src/*/Makefile.am, but keep the headers
list to feed to move-asn1-header-files.sh.
Adjust all #includes in src/*_common.h and elsewhere. In hnbap_common.h,
separate the ASN.1 "primitive" headers from the others, and include them
without a subdir path, as before.