ci: Check the API visibility

Check we don't accidentally add private headers to public ones, and that
all public headers are included in the public handy.h. We do so by
running the newly added lint/api-visibility.sh script during the build
stage. This script can be run locally too.
8 jobs for api-visibility in 13 minutes and 28 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed api-visibility #238979
librem5

00:03:01

passed build-debian-clang #238982
librem5

00:04:21

passed build-debian-gcc #238980
librem5

00:03:34

passed build-debian-gcc-static #238981
librem5

00:03:32

passed build-fedora-gcc #238983
librem5

00:02:52

 
  Docs
passed build-gtkdoc #238984
librem5

00:02:22

 
  Test
passed unit-test #238985
librem5

00:02:20

44.5%
 
  Package
passed package-debian #238986
librem5

00:02:50